Riding circles squares and diamonds inside each other helps the rider appreciate how important it is to ride accurate figures to improve the horses’ balance, and how much pressure and weight is necessary on the reins.
In an arena, first ride a correct 20 metre circle at one end or the other. Then turn the figure into a square by adding the corners. This will help the rider to use the outside rein to achieve corners, and of course how much inside leg is needed.
Ride this on both reins because your horse has a tendency to fall in on one rein and fall away on the other. When you can do this then, turn the square slightly around so that the points of a diamond are at X and A, or C and the other two equal distant from X on the track. On one way around the square will help you to understand how much aid pressure you need to stop your horse falling in and, the diamond will teach you how to stop your horse falling away out of his outside shoulder.
This is good for the Novice horse in trot. A more advanced horse can work this in canter.