Originally Posted by njkayaker

You need to be specific about what point you are talking about. The top of the pedal or something else.

Talking about the top of the pedal (where the cleat attaches):

• The center of the pedal axis (axle) on the crank is going in a circle.
• The top of the pedal is a bit "higher" than the pedal axis.
• If the pedal is kept horizontal throughout the stroke, the distance between the center of the crank and the top of the pedal is shorter with the crank arms horizontal than when the crank arms are vertical.
• I think this means pedal stroke isn't circular (but not by much).
• It's not a symmetric shape (ellipses are symmetrical).

People don't keep the pedal in the same orientation (relative to the ground) through the stroke. But that shouldn't matter much. The only way the top of the pedal moves in a circle is if the pedal is always orthogonal to the crank arm throughout the stroke.

A > B > C