doc: Add videos and pictures to quickstart guide

Add some quick videos and screen snapshots to the quickstart guide.

Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>

Makefile

@@ -164,6 +164,9 @@ help/$(TARGET).md: $(wildcard doc/*.md doc/calc-help/*.md doc/commands/*.md)
 	sed -e 's/DB48X/$(PRODUCT_NAME)/g' \
             -e 's/DM42/$(PRODUCT_MACHINE)/g' > $@
 	cp doc/*.png help/
+	mkdir -p help/img
+	rsync -av --delete doc/img/*.png help/img/
+
 check-ids: help/$(TARGET).md
 	@for I in $$(cpp -xc++ -D'ID(n)=n' src/ids.tbl | 		\
 		   sed -e 's/##//g' | sed -e 's/^#.*//g');		\

doc/2-Quickstart.md

@@ -1,10 +1,30 @@
 # Quickstart guide
 
 This quickstart guide will rapidly give you an overview of the capabilities of
-DB48X, and show you how to use it efficiently.
+DB48X, and show you how to use it efficiently. Make sure that you have
+[installed the latest version](#installation).
 
-[![Installation process](https://img.youtube.com/vi/rVWy4N0lBOI/maxresdefault.jpg)](https://www.youtube.com/watch?v=rVWy4N0lBOI&list=PLz1qkflzABy-Cs1R07zGB8A9K5Yjolmlf)
+The _ON_ / _EXIT_ button is at the bottom left of the calculator. It can be used
+to power the calculator on, but also to exit operations, for example aborting a
+data entry.
 
+DB48X is a RPL calculator, which means that:
+
+* It inherits the stack-based "reverse polish" approach to operations that has
+  been a central feature of practically all Hewlett-Packard scientific
+  calculators since the HP-35. You enter arguments to a functions by pushing
+  them on the stack, and the operation removes its arguments from the stack
+  before putting its result(s). Unlike earlier HP calculators, the RPL stack is
+  practically unlimited.
+
+  ![Stack and menus](img/stack-and-menus.png)
+
+* Unlike simpler calculators, it uses a _command line_ for data entry, with
+  advanced text editing capabilities, and a rich text-based command
+  language. One way to access the hundreds of available commands is by simply
+  typing their name.
+
+  ![Command-line and catalog](img/command-line-and-catalog.png)
 
 ## Arithmetic operations
 
@@ -17,6 +37,8 @@ _._, _5_, _ENTER_, _2_, _._, _8_, _×_, _+_. The result, `59.6`, shows on the
 stack. Prior to pressing the _+_ key, the intermediate results for the two
 multiplications, `49.8` and `9.8`, could be seen on the stack.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/e185f3e8-dd36-4beb-a6c5-03bf489d91a7"></video>
+
 RPL also supports the standard algebraic notation. Begin the computation with
 the _'()_ key. The editor contains quotes, `''` with the cursor between
 them. The cursor shows the latter `A`, indicating algebraic entry. Type _6_,
@@ -26,6 +48,8 @@ or `'6×8.3+3.5×2.8'`. Press `ENTER` and the expression shows up on the
 stack. Hitting the _=_ / _EVAL_ / _SPC_ key (located between the _._ and _+_
 keys) evaluates the expression, to get the result `59.6`.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/ba81f9f0-ec4d-4619-bf95-c56c14210fc3"></video>
+
 Algebraic and reverse-polish computations are equivalent, and can be mixed and
 matched during computations. Using one or the other is stricly a matter of
 preference. Algebraic data entry makes it easier to view the entire
@@ -39,6 +63,8 @@ in 8 slices. Using the RPL approach, we would type _2_, _2_, _ENTER_, _8_,
 _÷_. Using the algebraic notation, we would type _'()_, _2_, _2_, _÷_, _8_,
 _ENTER_ and then use the _=_ to perform the computation.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/89ebbf7a-f331-4729-a1b9-1527287daa3e"></video>
+
 With the default settings, you should see a mixed fraction, `2 ³/₄`. Unlike many
 calculators, DB48X by default perform exact computations on fractions instead of
 using approximate decimal numbers.
@@ -56,6 +82,8 @@ directly available on the keyboard.
 We can compute the length of the diagonal of a rectangle with sides 2m and 3m
 using the Pythagorean theorem, and display it in millimeters.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/899ad5f3-fd0b-4695-86bb-0b682a191422"></video>
+
 In RPL, we can type the following sequence: _2_, _x²_ (🟨 _C_), _3_, _x²_,
 _+_, _√x_ (_C_), _1_, _0_, _0_, _0_, _×_. The decimal result,
 `3 605.55127 546`, is shown on the stack. The digits in the whole part of the
@@ -75,6 +103,8 @@ In the algebraic expression, we have multiplied by 1000 first, whereas in the
 RPL case, we multiplied by 1000 last. We can also multiply by 1000 last in
 algebraic mode. There are at least two ways to do it.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/88cb7865-87cb-427e-b18b-33086bcbabd5"></video>
+
 A first method is to use the arrow key to exit the parentheses around the
 argument of the square root function, as follows: _'()_, _√x_,
 _2_, _x²_, _+_, _3_, _x²_, _▶︎_, _×_, _1_, _0_, _0_, _0_,
@@ -99,6 +129,8 @@ like:
 
 * If we need to reach 60 cm above ground, what is the required slope?
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/a90b32c4-a903-4421-a768-c6b6b2afddec"></video>
+
 In RPL, can answer the first question by typing _1_, _0_, _SIN_, _5_,
 _×_. The result is shown in scientific format as `8.68240 88833 5×₁₀⁻¹`.
 In algebraic mode, we would type _'()_, _5_, _×_, _SIN_, _1_, _0_, _ENTER_
@@ -124,6 +156,8 @@ The scientific notation may not be the most readable in that case. How do we
 display this result with three digits? We will use a *menu* for that. Menus are
 an essential component of the DB48X user interface.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/be997041-74f9-489b-9583-b94036b9dc33"></video>
+
 Let us type 🟨 _O_ (_Disp_). This shows the `DisplayModesMenu`. The menu
 occupies three rows at the bottom of the screen, with six columns. Menus can
 give a quick access to 18 functions directly, six more with a single shift 🟨,
@@ -152,24 +186,93 @@ hold the corresponding key until the help shows up. For instance, to get
 This also works for normal keyboard operations. For instance, if you hold the
 _SIN_ key, you will get the [help about the sine command](#sin).
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/55d312a4-3977-421e-9cdf-65d8b5ff5036"></video>
+
+You should refer to the on-line help whenever you have a question about a
+specific command.
+
+
+## Angle operations
+
+The _sin⁻¹_ command we used previously returns an *angle* which was shown in
+degrees, the default angle mode for DB48X. When applied to angles, the `Cycle`
+command on the _EEX_ key cycles between various angle units: degrees, radians,
+grads and pi-radians, i.e. a number of radians shown as a multiple of π.
+
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/5d23f388-b034-45cd-9d4d-7685b7f211f0"></video>
+
+The function also alternates between decimal and fractional representations of
+angles.
+
+In order to access angle-related functions, we can use the Tools key _⚙️_ which
+invokes the `ToolsMenu` command. That command picks up a menu that is suited for
+the value on the stack. For angles, this shows the `AnglesMenu`, which can be
+used to perform angle conversions directly.
+
+We can select the `→Deg` command to convert an angle to degrees by hitting the
+🟨 _F1_ key while the `AnglesMenu` is active, and similarly for `→Rad` with
+🟨 _F2_, and so on. To convert the angle to a Degrees/Minutes/Seconds (DMS)
+representation, we can select the `→DMS` using the 🟦 _F1_ key, since that
+function is on the second level of the menu.
+
+There is a quick way to manually enter angles in DMS format by using the _._
+more than once during data entry. For example, to enter 10°20′30″, you simply
+need to type _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _ENTER_.
+
+On the command-line, this shows up as `10°20′30_hms`. Once you hit the _ENTER_
+key, this shows on the stack as `10°20′30″`.
+
+Using _._ more while on the command-line lets you add fractions of a second, for
+example _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _._, _4_, _0_, _._, _5_, _0_,
+_ENTER_, which will show on the stack as `10°20′30″4/5`.
+
+You can add or subtract angles directly using normal arithmetic functions. For
+example, hitting the _+_ key will add angles, correctly adjusting the angle
+units as necessary.
+
 
 ## Complex number operations
 
+DB48X support complex numbers both in rectangular and polar (phasor) form.
+For example, in our effort to build a plank ramp, we may need more than one
+plank. How far and how high can you reach if you have a 5 meter plank with a
+slope of 10 degrees, followed by a 3 meters plank with a slope of 30 degrees?
+
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/a17d5404-ad05-4a4d-8c62-069f327b3428"></video>
+
+We can add two complex numbers in phasor form to answer that question.
+In order to enter the complex number representing the first plank, we need the
+`ComplexMenu`, which is activated with the _CPLX_ key (🟨 _G_). The _F1_ key
+will be used to enter complex numbers in rectangular form, and the _F2_ key to
+enter complex numbers in polar form.
+
+To solve our problem, we simply need to enter _CMPLX_ (🟨 _G_), then _5_, _F2_,
+_1_, _0_, _ENTER_ to enter the first complex number. The stack shows the complex
+value as `5∡10°`. We can enter the second complex number using _3_, _F2_, _3_,
+_0_, and add the two values using the _+_ key. The result shows as
+`7.522+2.368ⅈ`, which means that we can reach about 7.5 meters ahead and 2.3
+meters above ground.
 
 
-## Switching between DM42 and DB48X
+## Unit conversions
 
-**Checking that the DM42 firmware works with the DB48X QSPI file**
+If you are living in the United States, having the results in meters might not
+be convenient. You can use the DB48X built-in units in order to convert the
+result above into feet, yards or inches.
 
-**Running the DB48X program**
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/1fd54b22-5d1e-42bc-ac3a-2be5770422cf"></video>
 
-**Running the DM42 program**
+Select the `UnitMenu` with 🟨 _5_. This shows a catalog of unit categories. We
+can select the `Length` category using the _F4_ key. In order to indicate that
+our result is in meters, we select the `m` unit by hitting _F1_. Our result now
+shows as `7.522+2.368ⅈ m` We can then convert that result in yards by selecting
+the `→yd` command with the 🟨 _F2_ key.
 
-**Saving and restoring DM42 state**
+You can convert to other units in the `Length` units menu the same way. This
-
+menu is too large to fit on the screen, so the _F6_ key can be use to select the
-**Saving and restoring DB48X state**
+next page in the menu with more units, such as `in` or `mm`. Note that DB48X
-
+does not have a `NXT` key unlike HP calculators. Instead, when necessary, the
-**Shared state between the two programs**
+`NXT` and `PREV` features appear in the menu itself as _F6_ and 🟨 _F6_.
 
 
 ## Operations on whole numbers

help/db48x.md

@@ -934,10 +934,30 @@ programmed solution.
 # Quickstart guide
 
 This quickstart guide will rapidly give you an overview of the capabilities of
-DB48X, and show you how to use it efficiently.
+DB48X, and show you how to use it efficiently. Make sure that you have
+[installed the latest version](#installation).
 
-[![Installation process](https://img.youtube.com/vi/rVWy4N0lBOI/maxresdefault.jpg)](https://www.youtube.com/watch?v=rVWy4N0lBOI&list=PLz1qkflzABy-Cs1R07zGB8A9K5Yjolmlf)
+The _ON_ / _EXIT_ button is at the bottom left of the calculator. It can be used
+to power the calculator on, but also to exit operations, for example aborting a
+data entry.
 
+DB48X is a RPL calculator, which means that:
+
+* It inherits the stack-based "reverse polish" approach to operations that has
+  been a central feature of practically all Hewlett-Packard scientific
+  calculators since the HP-35. You enter arguments to a functions by pushing
+  them on the stack, and the operation removes its arguments from the stack
+  before putting its result(s). Unlike earlier HP calculators, the RPL stack is
+  practically unlimited.
+
+  ![Stack and menus](img/stack-and-menus.png)
+
+* Unlike simpler calculators, it uses a _command line_ for data entry, with
+  advanced text editing capabilities, and a rich text-based command
+  language. One way to access the hundreds of available commands is by simply
+  typing their name.
+
+  ![Command-line and catalog](img/command-line-and-catalog.png)
 
 ## Arithmetic operations
 
@@ -950,6 +970,8 @@ _._, _5_, _ENTER_, _2_, _._, _8_, _×_, _+_. The result, `59.6`, shows on the
 stack. Prior to pressing the _+_ key, the intermediate results for the two
 multiplications, `49.8` and `9.8`, could be seen on the stack.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/e185f3e8-dd36-4beb-a6c5-03bf489d91a7"></video>
+
 RPL also supports the standard algebraic notation. Begin the computation with
 the _'()_ key. The editor contains quotes, `''` with the cursor between
 them. The cursor shows the latter `A`, indicating algebraic entry. Type _6_,
@@ -959,6 +981,8 @@ or `'6×8.3+3.5×2.8'`. Press `ENTER` and the expression shows up on the
 stack. Hitting the _=_ / _EVAL_ / _SPC_ key (located between the _._ and _+_
 keys) evaluates the expression, to get the result `59.6`.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/ba81f9f0-ec4d-4619-bf95-c56c14210fc3"></video>
+
 Algebraic and reverse-polish computations are equivalent, and can be mixed and
 matched during computations. Using one or the other is stricly a matter of
 preference. Algebraic data entry makes it easier to view the entire
@@ -972,6 +996,8 @@ in 8 slices. Using the RPL approach, we would type _2_, _2_, _ENTER_, _8_,
 _÷_. Using the algebraic notation, we would type _'()_, _2_, _2_, _÷_, _8_,
 _ENTER_ and then use the _=_ to perform the computation.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/89ebbf7a-f331-4729-a1b9-1527287daa3e"></video>
+
 With the default settings, you should see a mixed fraction, `2 ³/₄`. Unlike many
 calculators, DB48X by default perform exact computations on fractions instead of
 using approximate decimal numbers.
@@ -989,6 +1015,8 @@ directly available on the keyboard.
 We can compute the length of the diagonal of a rectangle with sides 2m and 3m
 using the Pythagorean theorem, and display it in millimeters.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/899ad5f3-fd0b-4695-86bb-0b682a191422"></video>
+
 In RPL, we can type the following sequence: _2_, _x²_ (🟨 _C_), _3_, _x²_,
 _+_, _√x_ (_C_), _1_, _0_, _0_, _0_, _×_. The decimal result,
 `3 605.55127 546`, is shown on the stack. The digits in the whole part of the
@@ -1008,6 +1036,8 @@ In the algebraic expression, we have multiplied by 1000 first, whereas in the
 RPL case, we multiplied by 1000 last. We can also multiply by 1000 last in
 algebraic mode. There are at least two ways to do it.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/88cb7865-87cb-427e-b18b-33086bcbabd5"></video>
+
 A first method is to use the arrow key to exit the parentheses around the
 argument of the square root function, as follows: _'()_, _√x_,
 _2_, _x²_, _+_, _3_, _x²_, _▶︎_, _×_, _1_, _0_, _0_, _0_,
@@ -1032,6 +1062,8 @@ like:
 
 * If we need to reach 60 cm above ground, what is the required slope?
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/a90b32c4-a903-4421-a768-c6b6b2afddec"></video>
+
 In RPL, can answer the first question by typing _1_, _0_, _SIN_, _5_,
 _×_. The result is shown in scientific format as `8.68240 88833 5×₁₀⁻¹`.
 In algebraic mode, we would type _'()_, _5_, _×_, _SIN_, _1_, _0_, _ENTER_
@@ -1057,6 +1089,8 @@ The scientific notation may not be the most readable in that case. How do we
 display this result with three digits? We will use a *menu* for that. Menus are
 an essential component of the DB48X user interface.
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/be997041-74f9-489b-9583-b94036b9dc33"></video>
+
 Let us type 🟨 _O_ (_Disp_). This shows the `DisplayModesMenu`. The menu
 occupies three rows at the bottom of the screen, with six columns. Menus can
 give a quick access to 18 functions directly, six more with a single shift 🟨,
@@ -1085,24 +1119,93 @@ hold the corresponding key until the help shows up. For instance, to get
 This also works for normal keyboard operations. For instance, if you hold the
 _SIN_ key, you will get the [help about the sine command](#sin).
 
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/55d312a4-3977-421e-9cdf-65d8b5ff5036"></video>
+
+You should refer to the on-line help whenever you have a question about a
+specific command.
+
+
+## Angle operations
+
+The _sin⁻¹_ command we used previously returns an *angle* which was shown in
+degrees, the default angle mode for DB48X. When applied to angles, the `Cycle`
+command on the _EEX_ key cycles between various angle units: degrees, radians,
+grads and pi-radians, i.e. a number of radians shown as a multiple of π.
+
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/5d23f388-b034-45cd-9d4d-7685b7f211f0"></video>
+
+The function also alternates between decimal and fractional representations of
+angles.
+
+In order to access angle-related functions, we can use the Tools key _⚙️_ which
+invokes the `ToolsMenu` command. That command picks up a menu that is suited for
+the value on the stack. For angles, this shows the `AnglesMenu`, which can be
+used to perform angle conversions directly.
+
+We can select the `→Deg` command to convert an angle to degrees by hitting the
+🟨 _F1_ key while the `AnglesMenu` is active, and similarly for `→Rad` with
+🟨 _F2_, and so on. To convert the angle to a Degrees/Minutes/Seconds (DMS)
+representation, we can select the `→DMS` using the 🟦 _F1_ key, since that
+function is on the second level of the menu.
+
+There is a quick way to manually enter angles in DMS format by using the _._
+more than once during data entry. For example, to enter 10°20′30″, you simply
+need to type _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _ENTER_.
+
+On the command-line, this shows up as `10°20′30_hms`. Once you hit the _ENTER_
+key, this shows on the stack as `10°20′30″`.
+
+Using _._ more while on the command-line lets you add fractions of a second, for
+example _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _._, _4_, _0_, _._, _5_, _0_,
+_ENTER_, which will show on the stack as `10°20′30″4/5`.
+
+You can add or subtract angles directly using normal arithmetic functions. For
+example, hitting the _+_ key will add angles, correctly adjusting the angle
+units as necessary.
+
 
 ## Complex number operations
 
+DB48X support complex numbers both in rectangular and polar (phasor) form.
+For example, in our effort to build a plank ramp, we may need more than one
+plank. How far and how high can you reach if you have a 5 meter plank with a
+slope of 10 degrees, followed by a 3 meters plank with a slope of 30 degrees?
+
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/a17d5404-ad05-4a4d-8c62-069f327b3428"></video>
+
+We can add two complex numbers in phasor form to answer that question.
+In order to enter the complex number representing the first plank, we need the
+`ComplexMenu`, which is activated with the _CPLX_ key (🟨 _G_). The _F1_ key
+will be used to enter complex numbers in rectangular form, and the _F2_ key to
+enter complex numbers in polar form.
+
+To solve our problem, we simply need to enter _CMPLX_ (🟨 _G_), then _5_, _F2_,
+_1_, _0_, _ENTER_ to enter the first complex number. The stack shows the complex
+value as `5∡10°`. We can enter the second complex number using _3_, _F2_, _3_,
+_0_, and add the two values using the _+_ key. The result shows as
+`7.522+2.368ⅈ`, which means that we can reach about 7.5 meters ahead and 2.3
+meters above ground.
 
 
-## Switching between DM42 and DB48X
+## Unit conversions
 
-**Checking that the DM42 firmware works with the DB48X QSPI file**
+If you are living in the United States, having the results in meters might not
+be convenient. You can use the DB48X built-in units in order to convert the
+result above into feet, yards or inches.
 
-**Running the DB48X program**
+<video src="https://github.com/c3d/DB48X-on-DM42/assets/1695924/1fd54b22-5d1e-42bc-ac3a-2be5770422cf"></video>
 
-**Running the DM42 program**
+Select the `UnitMenu` with 🟨 _5_. This shows a catalog of unit categories. We
+can select the `Length` category using the _F4_ key. In order to indicate that
+our result is in meters, we select the `m` unit by hitting _F1_. Our result now
+shows as `7.522+2.368ⅈ m` We can then convert that result in yards by selecting
+the `→yd` command with the 🟨 _F2_ key.
 
-**Saving and restoring DM42 state**
+You can convert to other units in the `Length` units menu the same way. This
-
+menu is too large to fit on the screen, so the _F6_ key can be use to select the
-**Saving and restoring DB48X state**
+next page in the menu with more units, such as `in` or `mm`. Note that DB48X
-
+does not have a `NXT` key unlike HP calculators. Instead, when necessary, the
-**Shared state between the two programs**
+`NXT` and `PREV` features appear in the menu itself as _F6_ and 🟨 _F6_.
 
 
 ## Operations on whole numbers

help/db50x.md

@@ -934,10 +934,30 @@ programmed solution.
 # Quickstart guide
 
 This quickstart guide will rapidly give you an overview of the capabilities of
-DB50X, and show you how to use it efficiently.
+DB50X, and show you how to use it efficiently. Make sure that you have
+[installed the latest version](#installation).
 
-[![Installation process](https://img.youtube.com/vi/rVWy4N0lBOI/maxresdefault.jpg)](https://www.youtube.com/watch?v=rVWy4N0lBOI&list=PLz1qkflzABy-Cs1R07zGB8A9K5Yjolmlf)
+The _ON_ / _EXIT_ button is at the bottom left of the calculator. It can be used
+to power the calculator on, but also to exit operations, for example aborting a
+data entry.
 
+DB50X is a RPL calculator, which means that:
+
+* It inherits the stack-based "reverse polish" approach to operations that has
+  been a central feature of practically all Hewlett-Packard scientific
+  calculators since the HP-35. You enter arguments to a functions by pushing
+  them on the stack, and the operation removes its arguments from the stack
+  before putting its result(s). Unlike earlier HP calculators, the RPL stack is
+  practically unlimited.
+
+  ![Stack and menus](img/stack-and-menus.png)
+
+* Unlike simpler calculators, it uses a _command line_ for data entry, with
+  advanced text editing capabilities, and a rich text-based command
+  language. One way to access the hundreds of available commands is by simply
+  typing their name.
+
+  ![Command-line and catalog](img/command-line-and-catalog.png)
 
 ## Arithmetic operations
 
@@ -950,6 +970,8 @@ _._, _5_, _ENTER_, _2_, _._, _8_, _×_, _+_. The result, `59.6`, shows on the
 stack. Prior to pressing the _+_ key, the intermediate results for the two
 multiplications, `49.8` and `9.8`, could be seen on the stack.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/e185f3e8-dd36-4beb-a6c5-03bf489d91a7"></video>
+
 RPL also supports the standard algebraic notation. Begin the computation with
 the _'()_ key. The editor contains quotes, `''` with the cursor between
 them. The cursor shows the latter `A`, indicating algebraic entry. Type _6_,
@@ -959,6 +981,8 @@ or `'6×8.3+3.5×2.8'`. Press `ENTER` and the expression shows up on the
 stack. Hitting the _=_ / _EVAL_ / _SPC_ key (located between the _._ and _+_
 keys) evaluates the expression, to get the result `59.6`.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/ba81f9f0-ec4d-4619-bf95-c56c14210fc3"></video>
+
 Algebraic and reverse-polish computations are equivalent, and can be mixed and
 matched during computations. Using one or the other is stricly a matter of
 preference. Algebraic data entry makes it easier to view the entire
@@ -972,6 +996,8 @@ in 8 slices. Using the RPL approach, we would type _2_, _2_, _ENTER_, _8_,
 _÷_. Using the algebraic notation, we would type _'()_, _2_, _2_, _÷_, _8_,
 _ENTER_ and then use the _=_ to perform the computation.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/89ebbf7a-f331-4729-a1b9-1527287daa3e"></video>
+
 With the default settings, you should see a mixed fraction, `2 ³/₄`. Unlike many
 calculators, DB50X by default perform exact computations on fractions instead of
 using approximate decimal numbers.
@@ -989,6 +1015,8 @@ directly available on the keyboard.
 We can compute the length of the diagonal of a rectangle with sides 2m and 3m
 using the Pythagorean theorem, and display it in millimeters.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/899ad5f3-fd0b-4695-86bb-0b682a191422"></video>
+
 In RPL, we can type the following sequence: _2_, _x²_ (🟨 _C_), _3_, _x²_,
 _+_, _√x_ (_C_), _1_, _0_, _0_, _0_, _×_. The decimal result,
 `3 605.55127 546`, is shown on the stack. The digits in the whole part of the
@@ -1008,6 +1036,8 @@ In the algebraic expression, we have multiplied by 1000 first, whereas in the
 RPL case, we multiplied by 1000 last. We can also multiply by 1000 last in
 algebraic mode. There are at least two ways to do it.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/88cb7865-87cb-427e-b18b-33086bcbabd5"></video>
+
 A first method is to use the arrow key to exit the parentheses around the
 argument of the square root function, as follows: _'()_, _√x_,
 _2_, _x²_, _+_, _3_, _x²_, _▶︎_, _×_, _1_, _0_, _0_, _0_,
@@ -1032,6 +1062,8 @@ like:
 
 * If we need to reach 60 cm above ground, what is the required slope?
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/a90b32c4-a903-4421-a768-c6b6b2afddec"></video>
+
 In RPL, can answer the first question by typing _1_, _0_, _SIN_, _5_,
 _×_. The result is shown in scientific format as `8.68240 88833 5×₁₀⁻¹`.
 In algebraic mode, we would type _'()_, _5_, _×_, _SIN_, _1_, _0_, _ENTER_
@@ -1057,6 +1089,8 @@ The scientific notation may not be the most readable in that case. How do we
 display this result with three digits? We will use a *menu* for that. Menus are
 an essential component of the DB50X user interface.
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/be997041-74f9-489b-9583-b94036b9dc33"></video>
+
 Let us type 🟨 _O_ (_Disp_). This shows the `DisplayModesMenu`. The menu
 occupies three rows at the bottom of the screen, with six columns. Menus can
 give a quick access to 18 functions directly, six more with a single shift 🟨,
@@ -1085,24 +1119,93 @@ hold the corresponding key until the help shows up. For instance, to get
 This also works for normal keyboard operations. For instance, if you hold the
 _SIN_ key, you will get the [help about the sine command](#sin).
 
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/55d312a4-3977-421e-9cdf-65d8b5ff5036"></video>
+
+You should refer to the on-line help whenever you have a question about a
+specific command.
+
+
+## Angle operations
+
+The _sin⁻¹_ command we used previously returns an *angle* which was shown in
+degrees, the default angle mode for DB50X. When applied to angles, the `Cycle`
+command on the _EEX_ key cycles between various angle units: degrees, radians,
+grads and pi-radians, i.e. a number of radians shown as a multiple of π.
+
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/5d23f388-b034-45cd-9d4d-7685b7f211f0"></video>
+
+The function also alternates between decimal and fractional representations of
+angles.
+
+In order to access angle-related functions, we can use the Tools key _⚙️_ which
+invokes the `ToolsMenu` command. That command picks up a menu that is suited for
+the value on the stack. For angles, this shows the `AnglesMenu`, which can be
+used to perform angle conversions directly.
+
+We can select the `→Deg` command to convert an angle to degrees by hitting the
+🟨 _F1_ key while the `AnglesMenu` is active, and similarly for `→Rad` with
+🟨 _F2_, and so on. To convert the angle to a Degrees/Minutes/Seconds (DMS)
+representation, we can select the `→DMS` using the 🟦 _F1_ key, since that
+function is on the second level of the menu.
+
+There is a quick way to manually enter angles in DMS format by using the _._
+more than once during data entry. For example, to enter 10°20′30″, you simply
+need to type _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _ENTER_.
+
+On the command-line, this shows up as `10°20′30_hms`. Once you hit the _ENTER_
+key, this shows on the stack as `10°20′30″`.
+
+Using _._ more while on the command-line lets you add fractions of a second, for
+example _1_, _0_, _._, _2_, _0_, _._, _3_, _0_, _._, _4_, _0_, _._, _5_, _0_,
+_ENTER_, which will show on the stack as `10°20′30″4/5`.
+
+You can add or subtract angles directly using normal arithmetic functions. For
+example, hitting the _+_ key will add angles, correctly adjusting the angle
+units as necessary.
+
 
 ## Complex number operations
 
+DB50X support complex numbers both in rectangular and polar (phasor) form.
+For example, in our effort to build a plank ramp, we may need more than one
+plank. How far and how high can you reach if you have a 5 meter plank with a
+slope of 10 degrees, followed by a 3 meters plank with a slope of 30 degrees?
+
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/a17d5404-ad05-4a4d-8c62-069f327b3428"></video>
+
+We can add two complex numbers in phasor form to answer that question.
+In order to enter the complex number representing the first plank, we need the
+`ComplexMenu`, which is activated with the _CPLX_ key (🟨 _G_). The _F1_ key
+will be used to enter complex numbers in rectangular form, and the _F2_ key to
+enter complex numbers in polar form.
+
+To solve our problem, we simply need to enter _CMPLX_ (🟨 _G_), then _5_, _F2_,
+_1_, _0_, _ENTER_ to enter the first complex number. The stack shows the complex
+value as `5∡10°`. We can enter the second complex number using _3_, _F2_, _3_,
+_0_, and add the two values using the _+_ key. The result shows as
+`7.522+2.368ⅈ`, which means that we can reach about 7.5 meters ahead and 2.3
+meters above ground.
 
 
-## Switching between DM32 and DB50X
+## Unit conversions
 
-**Checking that the DM32 firmware works with the DB50X QSPI file**
+If you are living in the United States, having the results in meters might not
+be convenient. You can use the DB50X built-in units in order to convert the
+result above into feet, yards or inches.
 
-**Running the DB50X program**
+<video src="https://github.com/c3d/DB50X-on-DM32/assets/1695924/1fd54b22-5d1e-42bc-ac3a-2be5770422cf"></video>
 
-**Running the DM32 program**
+Select the `UnitMenu` with 🟨 _5_. This shows a catalog of unit categories. We
+can select the `Length` category using the _F4_ key. In order to indicate that
+our result is in meters, we select the `m` unit by hitting _F1_. Our result now
+shows as `7.522+2.368ⅈ m` We can then convert that result in yards by selecting
+the `→yd` command with the 🟨 _F2_ key.
 
-**Saving and restoring DM32 state**
+You can convert to other units in the `Length` units menu the same way. This
-
+menu is too large to fit on the screen, so the _F6_ key can be use to select the
-**Saving and restoring DB50X state**
+next page in the menu with more units, such as `in` or `mm`. Note that DB50X
-
+does not have a `NXT` key unlike HP calculators. Instead, when necessary, the
-**Shared state between the two programs**
+`NXT` and `PREV` features appear in the menu itself as _F6_ and 🟨 _F6_.
 
 
 ## Operations on whole numbers