Hilbert curve demo
The program below gives a demonstration of how Hilbert curves  can be drawn. It also demonstrates how threads can be used to prevent the application from locking up while a drawing is constructed. The two screenshots below are from the program running on Windows XP and Ubuntu 10.10.
Hilbert Curve program running on Ubuntu 10.10.
Hilbert Curve program running on Windows XP.
The demo program can be downloaded from github