Light travels in a straight line – that’s why shadows are the same shape as the object that makes them.Unless, of course, the object is at an angle. Or the light shines from a different position.
Lumineau, Fabrice, and Deepak Malhotra. "Shadow of the Contract: How Contract Structure Shapes Inter-Firm Dispute Resolution." Strategic Management Journal 32, no. 5 (May 2011): 532–555.