Hackerpet Lego Modmount
Hackerpet Mod Mount. The included stl should be compatible with Lego studs, but your tolerances, and thus results, may vary. i also included my fusion 360 sphere that I used to cut the part. I found it to be reasonably accurate. I have split it in two parts for easy printing. Flat sides down!
V2: flattened corners, to prevent breakage. Version labels, and side up labels.