Colibri said the joints of the legs can be any direction, and his example was that the foreleg joint, the elbow, is in reverse to the back leg knee.
But effectively the actual joint directional equivalent on each leg, is the foreleg’s elbow to the back leg’s ankle. The forward motion is achieved by having the two sets of limbs effectively jointed in the same ‘<’ formation.
Yes, they aren’t the equivalent in parallel joint comparison, but they are equivalent in relative placement from the ground up.
