If you look at the NES Mario sprites (which is what I assume you mean by classic), you'll see that his walking frames have 3 frames to them which cover the basic front to back motion I described earlier (I highlighted the motion in magenta):
![[Image: 1LJGLcd.png]](http://i.imgur.com/1LJGLcd.png)
They take advantage of the ambiguity between the front and back leg to save frames due to having no shading; you'd need at least twice as many frames if you made the front and back legs distinct.
They take advantage of the ambiguity between the front and back leg to save frames due to having no shading; you'd need at least twice as many frames if you made the front and back legs distinct.