I’m sorry I didn’t pass by here lately. I didn’t really disappear, i was just.. in the forth dimension :-)
Here’s a drawing I managed to make in Illustrator to explain the 4th dimension. I just followed the guides from this clip
( http://www.youtube.com/watch?v=ccws454YiVM&feature=related ), mind you that in that clip there was a little error and they made a second one for it ( http://www.youtube.com/watch?v=2pRZCoWY6TU&feature=related ).