Use the cursor to control the movement of the pen. To designate a circle center press 'c' to indicate the center, and 'p' to indicate the point on the circle. The circle will be drawn.
This is not a game just an example of using math. distance (the radius) = sqr root (( vertical * vertical )+(horiz * horiz)) Google 'Pythagorean theorem', if you would like to learn more.
