This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/5sBdqd7dekr
The curve in the center was borrowed/ripped from Thing:858911 by Hackermagnet here: http://www.thingiverse.com/thing:858911
Thanks to Hackermagnet for providing excellent SCAD code so I can learn how it's done.
Actually designed to hold a Raspberry Pi which fits a B+ for sure, or anything else that fits in the base and you want to be connected to a breadboard.