Peckish - I prefer the red square block.
I am struggling mightily with this. I'm afraid I have to copy the block several times and lay it out and play with it, as has been suggested.
I get very frustrated by my inability to visualize multiple blocks. It took me 5 minutes to figure out the difference between the 2 blocks you showed was black vs red middle square. Very, very hard for my brain to differentiate.
Thanks for your help.