This is a remix from this design: http://www.thingiverse.com/thing:391656. All credit goes to user "pilbara". I simply only needed one of these, not 4. Also, the original design did not work well on my 3D printer, since they print vertically as opposed to horizontally. So, I took it down to only 1 set of parts, and I made the holes slightly larger to accommodate M4 (4mm) hardware. This design allows you to print them flat, although you may have to print them at an angle to fit on your printer bed as I had to do (see pictures).