A line is a series of points laid down side-by-side. If we construct a line or flat surface out of points, in other words if we lay points side-by-side until we have line or flat surface, but there is no distance between the points that we lay down, we never get off the first point.
There has to be a distance between the points, which is the amazing discovery of string theory. It says points have distance between them. They are not points, but really little strings. If you lay little strings down, you can construct a line. But the math of string theory tells us that there are ten dimensions.
If we use little strings to create a flat surface, like, you make a table top out of triangular tiles, each triangular tile represents three strings, then you discover if you travel from tile to tile or point to point you can only travel in three directions! If you can only go from point to point in three directions, then, these three directions become three underlying dimensions on the two-dimensional flat surface, according to my logic. This flat surface, then, really has five dimensions.
If we construct a cube out of points, which have separation, then we discover we can only go in seven directions when we go from point to point in the three-dimensional space. These seven limited directions become seven dimensions according to my logic. Seven extra dimensions gives us a total of ten dimensions, and the number of extra dimensions is in agreement with string theory, so my logic for why the underlying directions are dimensions could be right.