For the first look a very simple puzzle. The point is that you have to place two objects next to each other to create a symmetrical shape. You cannot overlap two peaces, they must be in same plane. STL files are for 3D printing, SVG for laser engraving. The solution is in image packed in a ZIP file, don't open it if you want to try this yourself. 

This is a very old puzzle, I am not sure who invented it. Only the design is mine, the puzzle idea not.

If you upload Make, please don't upload solved puzzles. Thx.

More about it in this video: