Rotating the stage will cause the isogyres to move and change shape strikingly-moving from a position where the isogyres curve smoothly and are widely separated at their closest point, then gradually becoming more tightly curved / squarer at their midpoints as they approach each other ( a second isogyre appearing from out of the field of view if it was absent before ), then merging to form a maltese cross pattern very much like that of a uniaxial mineral.
