These little 30mm cube clips are a fun functional example of compliant mechanisms.

The single part flexes to act as a reverse action gripper. Use this to clip papers, bags, hold up photos, or any way you can imagine.

I printed mine with MatterHackers PRO Series PLA at 100% infill. PLA will lose clamping strength if left in the open position for a long period of time, especially at higher temperatures. ABS, PETG or ASA may be suitable options. Leave a comment if you have success with another filament!