Figure 1: The gait cycle. A schematic representation of gait cycle with stance (red) and swing (yellow) phases showed in the above line, whereas the line drawn in middle reported the gait cycle of the contralateral limb with swing (light blue) and stance (blue) phases. The black line drawn below showed the link with the Euclid’s problem to cut a straight line so that the proportion between the shorter part to the longer one is the same as the longer part to the whole .