Incredible SQUARE gears.

hello, a few years ago I came across on the Internet at the picture with square gears. I could not believe that they can be twisted. I tried to move the drawing in the sketch and 3D model. I got to move from image model and I decided to cut gears on a laser machine from the plywood.
YES, they revolve. The secret is a special form of denticles.

My model is available for download after registering on the site
https://grabcad.com/library/square-gear-1

also I want to emphasize the great models of the man
https://grabcad.com/trinityscsp/projects

he is a super expert
and he's got the same gears as mine, but he made them a year later !!!

You can find here a lot of interesting models of themselves to share with the world their
https://grabcad.com/library/sort/recent