A little inspiration from another hobby.
Technically all of the cubes have the same material, I just used the object index of the object info node to select different shaders in that material.
I am finding being so constrained allows the creativity to flow.
Had a similar idea this morning, but with a saw intead of the drill. 
Nifty little trick withe the shaders though.
That is funny, I also thought of a saw first, but after a bit of playing I thought I could capture the essence of a drill a bit better with cubes.
I guess great minds think alike 
