Use the UP and DOWN arrow keys to change the number on the right. When you press Button A, it “toggles” the pixels on the left. For example, if you have this setup… (Y is white, N is black…)
NNN
YNN
YYN
NNN
YYN
… on the left side, you should input the number 9 to get the setup looking like this…
YYY
NNY
NNY
NNY
NNY
… then input the number 7 to clear the left side and win. What it does is tests if a pixels on the right is white, and if so, it checks the color of that pixel, but on the left side. If that pixel (on the left side) is white, then it turns black. If the pixel is black, then it turns white.
In the thumbnail of this program, you can see an example. The red text is the order in which the program used to get the left figure. You can use the numbers backwards, to solve the game. (But the red text isn’t there unless you delete the REMs in the label MAINLOOP.
Get LowRes Coder to use this program.