First we have to make the distinction between MONO-lines and MULTIPLE-lines. I recommend using Mono-lines because this is the correct way of drawing, more accurate and faster. We should be able to draw a cube only from some soft lines and not overlap more lines to define the shape of the cube.
How do we build the cube?
a) we have two perpendicular lines, AB and CD. Draw AB longer than CD (so don’t draw them of the same size).
b) we trace the lines between the following points: B and C, B and D, D and A, A and C and we will form a rhomboid shape.
c) we prolong the BD line untill it intersects the AX line. And we do exactly the same with lines CD and BZ.
d) we intersect points X, Y and Z and we have the cube.
(AD is parallel with XY and YZ is parallel with DB)
Now we have the cube that can be inscribed in a sphere (like we all know that the circle can be inscribed in a square)
D point becomes the O point – the center of the sphere
Sides AX, XY, YZ, ZB, BC, CA are the sides of the hexagon named ACBZYX
(all sides are equal in size)