Technically, this is the right idea. However, it is simplistic, the lines are poorly crafted (inconsistant, haphazard) and the design's composition is pretty thoughtless. Also, I have seen this a thousand times.
3D hand portrait: I tried this using colored pencils in black, blue, purple, and orange. It worked well and was a big hit with my children. If using crayon or pencil, it helps if you shade the area where the curve and straight lines meet a little darker. I can think of all kinds of ways you could use this. Great art lesson or rainy day activity.