diff --git a/frustration2.rs b/frustration2.rs
index 7bbbf01..7b7f48f 100644
--- a/frustration2.rs
+++ b/frustration2.rs
@@ -78,7 +78,7 @@ enum Op {
     RET = 0xffe0, TOR = 0xffe2, RTO = 0xffe4, LD  = 0xffe6,
     ST  = 0xffe8, DUP = 0xffea, SWP = 0xffec, DRP = 0xffee,
     Q   = 0xfff0, ADD = 0xfff2, SFT = 0xfff4, OR  = 0xfff6,
-    INV = 0xfff8, ULT = 0xfffa, IO  = 0xfffc, NOP = 0xfffe,
+    AND = 0xfff8, INV = 0xfffa, GEQ = 0xfffc, IO  = 0xfffe,
 }
 
 const PRIMITIVES: [Primitive; 16] = [
@@ -135,14 +135,19 @@ const PRIMITIVES: [Primitive; 16] = [
         let v2 = x.dstack.pop();
         x.dstack.push(v1 | v2);
     },
+    | x | { // and
+        let v1 = x.dstack.pop();
+        let v2 = x.dstack.pop();
+        x.dstack.push(v1 & v2);
+    },
     | x | { // inv
         let v1 = x.dstack.pop();
         x.dstack.push(!v1);
     },
-    | x | { // ult
+    | x | { // geq (unsigned)
         let v1 = x.dstack.pop();
         let v2 = x.dstack.pop();
-        x.dstack.push(if v1 < v2 { 0xffff } else { 0 });
+        x.dstack.push(if v1 >= v2 { 0xffff } else { 0 });
     },
     | x | { // io
         let port = x.dstack.pop();
@@ -163,8 +168,7 @@ const PRIMITIVES: [Primitive; 16] = [
             }
             _ => {}
         }
-    },
-    | _x | { /* nop */ }
+    }
 ];
 
 /* --- The memory map ---
@@ -247,10 +251,6 @@ fn build_dictionary(c: &mut Core) {
     d.entry(); d.name(1, *b"-  ");  let sub = d.here;
     forth!(INV, Literal(1), ADD, ADD, RET);
 
-    // and ( a b -- a&b )
-    d.entry(); d.name(3, *b"and");  let and = d.here;
-    forth!(INV, SWP, INV, OR, INV, RET);
-
     let zero = d.here;
     forth!(Literal(0), RTO, DRP, RET);
 
@@ -260,7 +260,7 @@ fn build_dictionary(c: &mut Core) {
 
     // >= ( a b -- a>=b )  // note: signed comparison
     d.entry(); d.name(2, *b">= ");  let geq = d.here;
-    forth!(sub, Literal(0x4000), DUP, ADD, and, zero_eq, RET);
+    forth!(sub, Literal(0x4000), DUP, ADD, AND, zero_eq, RET);
 
     // = ( a b -- a=b )
     d.entry(); d.name(1, *b"=  ");  let eq = d.here;
@@ -291,11 +291,11 @@ fn build_dictionary(c: &mut Core) {
 
     // c@ ( a -- n )
     d.entry(); d.name(2, *b"c@ ");  let cld = d.here;
-    forth!(LD, Literal(0xff), and, RET);
+    forth!(LD, Literal(0xff), AND, RET);
 
     // c! ( n a -- )
     d.entry(); d.name(2, *b"c! ");  let cst = d.here;
-    forth!(DUP, LD, Literal(0xff), INV, and, SWP, TOR, OR, RTO, ST, RET);
+    forth!(DUP, LD, Literal(0xff), INV, AND, SWP, TOR, OR, RTO, ST, RET);
 
     // Load 1 letter into buffer.
     let stchar = d.here;
@@ -328,8 +328,8 @@ fn build_dictionary(c: &mut Core) {
     forth!(Literal(2), ADD, TOR,
            Literal(word_buf), DUP, Literal(2), ADD, LD, SWP, LD,
            RTO, DUP, TOR,
-           LD, Literal(0x0080), INV, and, eq,
-           SWP, RTO, Literal(2), ADD, LD, eq, and, RET);
+           LD, Literal(0x0080), INV, AND, eq,
+           SWP, RTO, Literal(2), ADD, LD, eq, AND, RET);
 
     let matched = d.here;
     forth!(Literal(6), ADD, RTO, DRP, RET);
@@ -382,7 +382,7 @@ fn build_dictionary(c: &mut Core) {
 
     // unsmudge ( -- )
     d.entry(); d.name(8 | 0x80, *b"uns");  let unsmudge = d.here;
-    forth!(word_addr, DUP, LD, Literal(0x0040), INV, and, SWP, ST, RET);
+    forth!(word_addr, DUP, LD, Literal(0x0040), INV, AND, SWP, ST, RET);
 
     // [ ( -- )
     d.entry(); d.name(1 | 0x80, *b"[  ");  let lbracket = d.here;
@@ -398,7 +398,7 @@ fn build_dictionary(c: &mut Core) {
            here, LD, Literal(2), ADD, here, ST, RET);
 
     let compile_call = d.here;
-    forth!(DUP, Literal(4), sub, LD, Literal(0x0080), and, state, LD, OR, Q, RET,
+    forth!(DUP, Literal(4), sub, LD, Literal(0x0080), AND, state, LD, OR, Q, RET,
            comma, RTO, DRP, RET);
 
     let compile_lit = d.here;
@@ -473,13 +473,12 @@ fn build_dictionary(c: &mut Core) {
     d.entry(); d.name(1, *b"+  "); forth!(ADD, RET);
     d.entry(); d.name(5, *b"shi"); forth!(SFT, RET);
     d.entry(); d.name(2, *b"or "); forth!(OR, RET);
-    d.entry(); d.name(6, *b"inv"); forth!(INV, RET);
-    d.entry(); d.name(2, *b"u< "); forth!(ULT, RET);
-    d.entry(); d.name(2, *b"io "); forth!(IO, RET);
+    d.entry(); d.name(3, *b"and"); forth!(AND, RET);
+    d.entry(); d.name(3, *b"inv"); forth!(INV, RET);
+    d.entry(); d.name(3, *b"geq"); forth!(GEQ, RET);
+    d.entry(); d.name(2, *b"io "); let io = d.here; forth!(IO, RET);
 
-    d.entry(); d.name(3, *b"nop"); let nop = d.here; forth!(NOP, RET);
-
-    d.c.store(latest_ptr, nop-6);
+    d.c.store(latest_ptr, io-6);
     d.c.store(here_ptr, d.here);
     d.c.store(state_ptr, 0xffff);
     d.c.store(0, quit);