|(require htdp/show-queen)||package: htdp-lib|
The teachpack provides the function show-queen, which implements a GUI for exploring the n-queens problem.
In the GUI window that show-queen opens, the red and orange dots show where the queens are. The green dot shows where the mouse cursor is. Each queen that threatens the green spot is shown in red, and the queens that do not threaten the green spot are shown in orange.