Further development of the Butterfly for Valentine model, I've opted for a leaf rather than a tree stump for the butterfly to sit on. I thought it looked a little more elegant. I've also made the box squarer and adjusted the lengths of the linkages a little to change the range of movement of the wings. Finally I've tilted the butterfly a little so that it is sloping upwards a little. I've based the wings on a monarch butterfly. 

From the side you can see where the pendulum links to the wings and how the leaf connects to the box top.

I just need to add a butterfly body and some colour and we're done!