Cube drawing is now done by drawing 2 triangle instead of 1 quare per face.

Why?

Look at this benchmark (time per 10 000 drawing)
Execution time was 665 ms. for drawing with 1 square per face
Execution time was 149 ms. for drawing with 2 triangle per face
Execution time was 716 ms. for drawing with 1 square per face
Execution time was 152 ms. for drawing with 2 triangle per face
Execution time was 707 ms. for drawing with 1 square per face