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.
Step 2: Cut the Thick Cardboard
Step 3: Glue the Side Plates
they are glued right side up, the right angles against the corners, the 45 degree angles up, and the edges that will sustain the mirror go up, away from the back side of the box.
Step 4: The Mirror Lies Down
I use a Glue gun to fix the thing, after I glue it with just plain UHU. A mirror is a heavy piece of glass...
Note that a space is left to the front of the box, you have to put your hand on the box, later.
Step 5: Cut a Square, Up Front
Step 6: Two Diagonals
This is, in essence, a Periscope with a see-trough part, so the bottom and back part, where the remaining 2 45º ramps are, will have a round hole, about 4Cm diameter, cut, and the center of the circle will be set by drawing back the lines, so you'll get another square, bu this time, just use the corners to draw those diagonals, to find the center of the peeping hole's circle
Step 7: The Peeping Hole
Real simple like.
Step 8: The Acrylic Goes Here
Step 9: The Paper Goes In..
Step 10: Fold It, Tape It
Step 11: What You See, When You Draw
As this is a 2-way glass, you can also see a hand, and since your eyes are far better at double lighting than ANY camera, you can draw all those lines, until you have a sketch.
Step 12: 13 - High Contrast
Step 13: The Box!
Step 14: Final Notes on a Scheme
The Laser cut gizmo is available here: