http://rosettacode.org/wiki/Circles_of_given_radius_through_two_points#J http://rosettacode.org/wiki/Mad_Libs#J Mad Libs uses an associative array class of general interest. Circles uses the complex plane. Complex numbers often simplify 2D work.