This shifter design was intended to fit into position in a similar way to a real shifter. It has a spring that returns it to its central position and a locking system that keeps it in every position.

The only element that is not 3D printed is a 5cm long m4 screw.

It is possible that depending on the screw you use, the head is different and does not fit correctly on the support piece. I've tried different screws and most of them work properly, so if you find one that doesn't, I ask you to let me know.
Every piece is built by locking in place, more info in the pictures.