One-sided Bridged Triamonds
If you join three equilateral triangles at their sides you get a trapezium. If connections at the corners are also allowed, you get 16 different one-sided pieces and they are called bridged
or rounded triamonds. A lot of figures which can be constructed with these pieces are shown at www.abarothsworld.com or www.logelium.de. The obj-files for each piece and a svg-file for all pieces is provided.