How do you convert two 2d into 3d?

Answer 1

To convert from 2 dimensions to 3 dimensions requires adding a third dimension:

If you start with a zero-dimension point and pull it out in a direction, you create a one-dimensional line as you go.

If you now take this line and pull it out in a direction perpendicular to it, drawing lines between the end points you create a two-dimensional rectangle as you go.

Now if you take the rectangle and pull it out in a direction perpendicular to the plane in which it lies, drawing lines between the corresponding vertices you create a three-dimensional cuboid as you go.