Dimension thing measure
(of physical extension)
regular object
(all right angles, same lengths)
0D point (none) ˙
1D line (curve) length line segment curves:
2D plane (surface) area square surfaces:
3D space volume cube
4D can't "see" it. Exists mathematically. Each dimension is a variable, eg. time,$,calories,length,weight etc. tesseract/hypercube The universe (spacetime)
5,6...∞ get used to it