particles_main:
NVIDIA's particle framework is implemented in pyhton. For visualization vpython is used. 
Todo:
1. use numpy arrays
2. get rid of loops
3. paralleliziation

deformable:
Müller[1]'s rigid and linear shape matching implementations. A cube which consists of 9 circles is falling down.
for rigid set rigid_match to True, for linear deformation set rigid_match and quadratic_match to False.