4DTris (by Simon Laszlo) is a Blockout clone extended to the 4th dimension available for Windows and Linux platforms. It uses OpenGL and SDL for 3D rendering. It’s an open source project released under the GPL licence.
To get a better understanding of the representation of 4D shape projected on a 2D display, you can have a look at the Ken Perlin's 4D java applet.
|An hyper cube||