They love the effect and can't get over how "sticky-outy" it becomes.
It's important to start with a top, then add three vertical edges and the bottom two edges. Its a great way to reinforce all the previous 3D mathematical language that they have learned. Words like face, edge, corner, diagonal, vertical and horizontal are all covered. When the grey and black tones are added the whole picture really comes alive and the children want to experiment with holes in the larger blocks.
I had to bribe most of them to finish and go home at the end of the day!