Coordinating four limbs
Consider the coordination of a horse’s four limbs. Now we have four muscle control circuits, one for each limb.
In addition to the mutual crossed inhibition between the left and the right circuits, inhibitory connections exist between the front and the rear legs on the same sides.
This circuit can generate trotting.
A diagram in which two blue circles and two pink circles form the corners of a square. The circle in the top left corner is blue and is labeled Left front. The circle in the top right corner is pink and is labeled Right front. The circle in the bottom left corner is pink and is labeled Left rear. The circle in the bottom right corner is blue and is labeled Right rear. The circles each have a pair of T-shaped projections extending in the direction of two of the other circles, forming the sides of a square. The Left front circle projects toward the Right front and Left rear. The Right front circle projects toward the Left front and Right rear. The Right rear circle projects toward the Left rear and Right front. The Left rear circle projects toward the Left front and Right rear.