The first small sample I made was a simple 4-bar linkage. However, by attaching it to the first join of the thumb, there is a lot more flexibility in one of the bars than usual.

Make sure to play with sound

This second sample was a way of exploring how expanding and contracting a tube with folds would change the shape. Each fold has a different fold line for the middle and as a result changes shape in a non-uniform matter.

An expanding and contracting bracer

I had originally made 2 of the simple tendon actuated joints with the plan of making something that attaches to the fingers. I soon realized that I could make actuating bunny ears.
Unfortunately the friction between the string and cardboard at the bend is stopping a lot of the restoring force. In my test I have some else pulling the lines, however it would be relatively simple to attach the strings to the base of the neck such that the ears move when you look down.

Bunny Bunny