Flexi Block Wheel Replacement

My son got an incomplete bucket of these "Flexiblocks" from 1988(!!!) and I figured it wouldn't be too hard to re-engineer a working replacement for any part he was missing so he could have a complete set. So I did. Then I figured that maybe someday someone else might need a replacement for a single part. So here is the first replacement part I designed, the "wheel" or "flexiwheel".