Batarang Pin/Badge

Bought a cheap set of pin backs (Amazon link below), now trying to 3D print stuff to attach them to. To start off, here's a batarang.

Dimensions: 3.6cm long x 2cm wide x 0.8cm high

Amazon link to pin backs: http://www.amazon.ca/Pins-Brooches-Jewelry-Crafts-Backs/dp/B000RB3RRA