Don't forget, my computer (I have a mac) doesn't project the background images. I have to go into pic set up mode (apple, shift, 4) so I can see it, or I have to take a thumbnail, so I was at a disadvantage there. Maybe you can fix it?
It's actually easy if you can remember the pattern. Here's a tip: use the space invaders background and then reflect the positions of the space invaders.