a childproof latch for double doors. automatically moves aside when door closes. The doors must have a pillar between them that is flush with the face of the doors. The stl is for a 3/4" pillar, but you can edit the freecad file for your specific door

print at 4 shells at 40% infill

predrill and attach to center pillar with a 1" #6 screw. make sure screw is loose enough for the latch to move freely. install close enough to the door handles so that you can open the door one handed and flick the latch aside with a single finger.