Any tips on making map Piece icons?

[HwitVlf]

I've always struggled with icons myself. I made that tool to auto generate 10,000 icons, but they're not really user friendly for small sets. The tool assembles each icon from a set of quarter-icons. In this case, the quarters had numbers 0-9. I could adapt it to use other quarter-icons, but I can't picture that being very useful for making "easy to comprehend" icon sets. If you'd like the et of 10,000 auto generated let me know.