How does an OTF knife mechanism look like?

The mechanism of an OTF knife is quite complicated as you can see on these pics and in the video. The example shown is an Out the Front automatic knife with a DA (double-action) function. This Double-action OTF knife deploys and retracts with a multifunction lever and spring design. Maybe you get inspired and try to build your own homemade OTF knife. However, I think you need to be a quite experienced knife maker.

 pictures of the deployed OTF knife, showing the mechanism in detail