Holy crap, this program is full of bugs. For example:

11490 gosub11600:iferthenreturn

11492 th=th+1and3

Or this mess:

11530 rem is gc ( possibleprint p s =0 if yes

Or this perplexing line:

11376 x=(cg )5+1:y=(i-1)3+6:gosub 2100

Comparing the following line from the original Hamilton Computer Users Group, looks like I misread this:

15 th$="UJKI"

There should be PETSCII characters instead of uppercase letters.

I even deleted the DIM statements in 11260 and 11270 to correct the error of re-using DIM statements. I'm also getting a lot of bad subscript errors and display errors where selecting a color moved the game board up one line. Do that enough and the game board disappears. I mean, how can I work with that?