Oh, hey, sorry. I did find out, and it's nothing very complicated: The wiper moves out about 10cms during rotation. That distance, applied to a circle with a ra

Oh, hey, sorry. I did find out, and it's nothing very complicated: The wiper moves out about 10cms during rotation. That distance, applied to a circle with a radius of 10 cm is a large distortion (the inside track), while applied to the larger outside radius just turns it into a round rectangle.