Triangle cutouts in my cube

When I run the program the left and right sides have cutouts in them. It’s supposed to be a cube.
I can’t figure out the problem or what makes those sides different at all.

The ordering of the vertices in your last two quads (‘Right’ and ‘Left’) is incorrect. I assume you know that you can’t list vertices in any order. They must be listed in the order that traces around the outside of the quad (i.e. specifying the edges of the quad). In your last two quads you have specified edges that cut through the diagonal of the quad. The correction is simple, just switch the 3rd and 4th vertex commands in your ‘Right’ and ‘Left’ quads. BTW - if you run into a problem like this again, draw the object in wireframe, which shows the quad or poly edges clearly. Then things will make sense to you.

Thank you, I can’t believe I missed that.