I'm wondering how you create the foot diagrams you have on the site.

More or less by default, I've been asked to take over teaching some very basic beginning couples lessons. While I don't care for them much, some students with different learning styles have requested foot diagrams. I have software that allows me to create animated foot patterns, but it doesn't seem to print well. Yours, on the other hand, seem nicely done. Is there a software you can recommend, or shareware? My budget for this is virtually non-existent.