Cavaletti to a fence

Tonight we did a new exercise.  John had three cavaletti set on a circle (so the insides were closer together than the outsides), and we rode them first at the trot, then at the canter.  My job was to bend Duke around my inside leg, get him lined up properly, keep my leg on, but then let him figure it out.
After we did that both directions, then we rode the cavaletti to a ground pole, over a vertical, over another ground pole.  First we went to the right, and I had a hard time with making the correct line to make the center of the fence be a circle with the cavaletti (even though I could totally see it).  When we changed directions, it was very easy.  Afterwards, John said that's because from the left, it was a seven stride line to the fence, but from the right, it was a 20 stride line.  That was pretty fascinating.  So my eye can see 7 strides, but not 20.
This was a straightforward looking, but not simple, exercise.  It highlighted how important it is to be precise.
From the right, John had me counterbend Duke, but if the jump was at 12, I did this at 9, so by the time I got to 10, I was bending him back and using that to bend us through the turn.  When I lined up the bend ahead of time, the cavaletti and the jump were smooth sailing.  If I messed up the angle of the circle or the bend, I could tell instantly.  It was a good exercise.