craigd:

It's easy to see the actual dynamics.

1. Make a circle with your thumb and forefinger, like the 'OK' sign.

2. Extend a finger of the other hand behind it, so you see mostly the center knuckle.

3. Now tilt the finger so when you view it through the circle you see all of the finger from tip to bottom knuckle.

The circle is your pattern and the laying down finger is the ground.

It's simple as that, and has nothing to do with time of arrival of the shot pellets.

"The price of good shotgunnery is constant practice" - Fred Kimble