PRIMAL PLANE DUAL PLANE ------------------------------------------------------- point p : (a, b) <=> line p*: y=ax-b line l : y=ax+b <=> point l*: (a, -b)
Instructions:
The left plane is the primal plane, the right plane is the dual plane. You may place points, lines, and line segments in the primal plane, and see how they show up in the dual plane.
Place point P by clicking the mouse at P.
Place line PQ by holding Control, clicking the mouse at P, and dragging to Q.
Place line segment PQ by holding Shift, clicking the mouse at P, and dragging to Q.