4DRoom

4DRoom  is an extension of the 4Dice app that puts the viewer INSIDE  a 3D cube, for analogy-based tutorials,
and then inside an actual 4D hypercubic room to explore 4D space.  Instead of a square wall, as one sees from inside
a 3D die, the center of the view is a cube, one of the
8 cubic walls surrounding the center of a hypercubic
room.
 
4DRoom also introduces a Virtual Reality feature under the
"accelerometer" option that lets one rotate the device left and 
right in space to substitute for the 4D rotation controlled by 
2-finger left-right drag.  This gives a good virtual impression
of actually being inside a 4D room.