The lizard's flexing body provided a conceptual challenge. The problem with the lizard was that because the body flexes the hips are constantly in motion whereas in previous creatures the hips remained fixed. The foot movement had to be dissociated from the calculation of the legs so that the foot movement could remain the same while the hips moved. In practice this turned out to be relatively easy.
The addition of a foot to the end of a leg also required some adjustment of the bugleg macro because if it remained flat while the leg was lifted it looked very unnatural. The bugleg macros were adjusted to output a foot angle for rotating the foot while the leg was off the ground.
The bisection method was also used to ensure that the the body remained the same length. The distance between the tail tip and back and front mean hip positions change as the lizard moves in order to ensure the body length remains the same.
For the lizard I added the blob limb to the conslimb macros because cylinders and ovoids didn't look right for something which is supposed to have an endoskeleton.
During the construction of the lizard I implemented the spines macro for adding the spines to it's back.
