I believe most people regard the 4th dimension as duration (time),
So if you could hypothetically see the 4th dimension the cube and it's parts would be seen from it's creation to when it, well, ceases to be. look at this:
YouTube - Imagining the Tenth Dimension - Rob Bryanton [FULL CLIP]
Around the 2:50 mark they talk about the 4th dimension theory, and all the dimensions up to the 9th. Purely theory but interesting.