diff --git a/projects/examples/demos/logic.tal b/projects/examples/demos/logic.tal
index ee74619..7a0393d 100644
--- a/projects/examples/demos/logic.tal
+++ b/projects/examples/demos/logic.tal
@@ -49,8 +49,6 @@
 	&x $2 &y $2 &x2 $2 &y2 $2
 @input
 	&a $1 &b $1
-@center
-	&x $2 &y $2
 @pointer
 	&x $2 &y $2
 
@@ -66,13 +64,11 @@
 
 	;on-mouse   .Mouse/vector DEO2
 
-	.Screen/width DEI2 2//
-		DUP2 .center/x STZ2
+	.Screen/width DEI2 2// 
 		DUP2 #0040 -- .a-frame/x STZ2 DUP2 #0040 ++ .a-frame/x2 STZ2
 		DUP2 #0040 -- .b-frame/x STZ2 #0040 ++ .b-frame/x2 STZ2
 
-	.Screen/height DEI2 2//
-		DUP2 .center/y STZ2
+	.Screen/height DEI2 2// #0020 --
 		DUP2 #0010 -- .a-frame/y STZ2 DUP2 #0000 ++ .a-frame/y2 STZ2
 		DUP2 .b-frame/y STZ2 #0010 ++ .b-frame/y2 STZ2
 
@@ -125,46 +121,57 @@ BRK
 
 	.a-frame/x LDZ2  .Screen/x DEO2
 	.a-frame/y LDZ2  .Screen/y DEO2
-	.input/a LDZ ;draw-byte JSR2
+	.input/a LDZ #01 ;draw-byte JSR2
 
 	.b-frame/x LDZ2 .Screen/x DEO2
 	.b-frame/y LDZ2 .Screen/y DEO2
-	.input/b LDZ ;draw-byte JSR2
+	.input/b LDZ #01 ;draw-byte JSR2
+
+	.b-frame/x LDZ2 .Screen/x DEO2
+	.Screen/y DEI2 #000d ++ .Screen/y DEO2
+	.input LDZ2 AND #03 ;draw-byte JSR2
+
+	.b-frame/x LDZ2 .Screen/x DEO2
+	.Screen/y DEI2 #000d ++ .Screen/y DEO2
+	.input LDZ2 ORA #03 ;draw-byte JSR2
+
+	.b-frame/x LDZ2 .Screen/x DEO2
+	.Screen/y DEI2 #000d ++ .Screen/y DEO2
+	.input LDZ2 EOR #03 ;draw-byte JSR2
 
 RTN
 
 @draw-byte ( value -- )
 
-	STH
+	STH STH
 	#0800
 	&loop
 		DUP #07 SWP -
-		STHkr SWP SFT #01 AND ;draw-bit JSR2
+		STHkr SWP SFT #01 AND OVRr STHr ;draw-bit JSR2
 		INC GTHk ,&loop JCN
 	POP2
 	.Screen/y DEI2 #0003 ++ .Screen/y DEO2
 	STHr ;draw-hex JSR2
+	POPr
 
 RTN
 
-@draw-bit ( value -- )
+@draw-bit ( value color -- )
 
-	STH
+	STH STH
 
 	#05 .Screen/auto DEO
 	;button-icns/off [ #00 STHkr 20* ++ ] .Screen/addr DEO2
-	#01 .Screen/sprite DEO
-	#01 .Screen/sprite DEO
+	OVRr STHr .Screen/sprite DEO
+	OVRr STHr .Screen/sprite DEO
 	.Screen/y DEI2 #0008 ++ .Screen/y DEO2
 	.Screen/x DEI2 #0010 -- .Screen/x DEO2
-	
-	#01 .Screen/sprite DEO
-	#01 .Screen/sprite DEO
-
+	OVRr STHr .Screen/sprite DEO
+	OVRr STHr .Screen/sprite DEO
 	#00 .Screen/auto DEO
 	.Screen/y DEI2 #0008 -- .Screen/y DEO2
 
-	POPr
+	POPr POPr
 
 RTN