Shadow of a Square Under a Point Source of Light
- Jake Hall
r controls the size of the square Point S is the light source, and controls the height of the light source (the light source S is located at ) Point P controls the center of the square, and the coordinates of P are Point Q controls the orientation of the square (think of Q as a knob on a joystick, where the joystick is perpendicular and attached to the square at P). θ tilts the square and φ rotates it about a vertical axis through its center). You can also move point A to spin the square about the PQ axis.