The following grid has been constructed using the shapes of unfolded cubes.
Determine the minimum number of shapes (red and green) needed to cover the blue grid. The shapes may overlap, but must remain in their original scale.
Rotations of the shapes are accepted, but not mirrorings. The shapes should cover all blue squares and no white squares. If you are not giving a fancy graphics solution, the solution should at least contain a reasonable justification for your number.