7.6 Modify the program of Figure 7.4 for the case of three-dimensional blocks and boxes. The structure of the program and the main principles will remain the same, so that relatively straightforward modifications are needed: (1) dimensions and positions become three-dimensional, like dim(5.0, 3.0, 2.0); (2) instead of two possible orientations of blocks, there will now be six (resulting from 90 degree rotations about three axes X, Y and Z); (3) the no-overlap condition between rectangles being 'before' or 'after' in either X or Y directions will now have to include also the two cases for the Z direction.