gridfinity baseplate joiner

I haven't actually tested with more than 1 baseplate, but it's slotted so should fit. you'll need 4 to join 2 plates if you want them leveled. Very lazy design but there's nothing else for this right now. https://cad.onshape.com/documents/521ae473fa26507e274a4eb9/w/bce1febc4bb83c9aaf1e6bf5/e/202fc9cdde63df320038427c oncad of design.

cc attribution or whatever Zach licensed his design as, I don't care.