I have TPU.. what in gods name do I need a hinge for?  

Modeling the hinges as strips of TPU.  Eliminating the return spring and modeling the slots in the base at an angle, so it naturally wants to open.

Had a brainstorm..  What if I used fishing line instead of TPU strands, and pulled on the outer edges?  The petals may curl in when closing!  

Going for it.  

I can't actually model the holes for the fishing line as this would interrupt my single layer print causing an uneven pattern.  I'll have to wing that part.

So... the petal.

The raised part in the center will be clear PLA, acting as a light pipe to the central clear PLA of the first layer.

Firing up the printer, and getting it loaded with TPU and PLA.