0: A dot
1: A line (Width... but "Width" can not exist without the others)
2: A square (Length... put that together with Width and you have depth perception. EDIT: Correction... No it doesn't.)
3: A cube (3D... there is a foward, a backward, a left & right and an up and down... plus inbetween or the dot in the middle... or rather the end... or is it the beginning? But the end and/or beginning is impossible to describe as we don't know where or what it is.
4: Time (Disputable)
5: Space (Disputable)
6: Matter (Appearntly, it's believed that this is a dimension)