rename figures folder

week7/img/as.mp4

week7/img/beam_bending.mp4

week7/img/beam_bending_large.mp4

week7/img/brittle_fall.mp4

week7/img/deformable_fall.mp4

week7/img/falling_objects.mp4

week7/img/liquid_fall.mp4

week7/img/my_people.mp4

week7/img/not_a_beam.gif

week7/img/rigid_fall.mp4

week7/img/solid_fall.mp4

week7/img/solid_fall_instability.mp4

week7/img/viscous_fall.mp4

week7/img/wrong_fixed_beam.gif