It's as easy as it gets, one cardboard box, some extra thick cardboard from another box, a mirror, and a piece of glass, or transparent acrylic.
Cut the cardboard, glue it, and you've made a Drawing Machine, with a 2-way glass, where you see the scene in front of you, and the paper where you draw!
Draw the lines, as drawing on a window, and you are both drawing, and gradually learning to imagine that same glass in front of any scene, one day.
Thanks for the rectification about drafting, rimar2000 :)
Also, Kiteman, here's the actual Illustration, from the 1923 "The boy mechanic" book available on the Net via Project Guttemberg.
Step 1: I assume you know how to draw a line...
Because you have to cut a pair of these shapes, in order to glue them into the inside of the box.