Interlocked rings mechanical toy. Sample printed with Ultimaker 2 on "Normal" print settings with a 0.46 nozzle.
I've added another STL file with 0.5mm gap between rings for those who get the original fused together, and also the Solidworks file for those who would like to experiment and change it on their own. Check for "gap" and "width" global variables.
0.2 layer hight, 0.46 nozzle