grid-pix, block-pix, number-tetra, ERRORS

Designed grid-pix, block-pix, and number-tetra. All have check-expects
which work.

MAJOR MISSING THING WHICH IS MAKING CODE GO: "OH, OH GOD WHY. OH GOD.
WHY. OH."

Tetra is not defined as a structure so all of our tetras are producing
errors because you can't say: (make-tetra ...)

I'm gonna let you take care of that because I am really tired at this
point and need a bit of sleep. :-)