Web site : www.bellwoodwork.com Puzzle Making for Woodworkers Donald Bell SFW Meeting, January 2011 Email : donald@marchland.org Web site : www.bellwoodwork.com

Puzzle Making for Woodworkers What makes a good puzzle? It should be easy to describe Fairly easy to make (either one or many) Not trivial to solve, but not dauntingly difficult either (solving time between 10 and 30 minutes, perhaps) The “look and feel” should be attractive There should be a surprise – either an “Aha!” factor or several puzzles in one

Puzzle Making for Woodworkers The puzzle-maker’s progress Solving other people’s puzzles Copying other people’s puzzles Modifying other people’s puzzles Creating original puzzles of your own Developing the manufacturing processes Documentation, packaging, sharing …

Different kinds of puzzle illustrated here put-together puzzles (2D) - put-together puzzles (3D) - "steady hand" puzzles - sequential puzzles Also (but not shown here) take-apart puzzles - (especially "burr" puzzles) - scroll-saw puzzles - sliding block puzzles - secret compartment boxes

More kinds of puzzle illustrated here (back cover of same book) put-together puzzles - "steady hand" puzzles - sequential puzzles Also (not really puzzles) magic tricks - games of skill

The “Blockhead” Puzzle - Easy to describe Not hard to make Not trivial to solve - Definitely an “Aha!” moment when you work out how to do it

A Brief Tour of the Workshop Band Saw Record Power BS 350 1½ HP cut depth 230mm, throat 340mm

Woodturning Lathe Record Power, Model CL3 ¾ HP, 5-speed belt drive

Table Saw Record Power TS200SB 2 HP, 4000 rpm 250mm (10") blade Sliding Beam (605mm travel)

Sliding Beam, Mitre Fence, 45 degree tilt

Disk Sander Clarke CDS 300 300mm diameter 1 HP, 1450 rpm

Radial Arm Drill Press Axminster AWBRD550 ¾ HP, 5 speed belt drive

Portable Router Clarke Contractor CR2 3 HP, 21000 rpm ½" collet

The Puzzle Maker's Toolkit

A few puzzles for you to play with – this is a secret opening box (there is something under that thumb!)

A well-known, easy to make puzzle The "Soma" Cube Four small cubes can be put together in eight different ways, including a straight stick and a square. The other six pieces, plus a 3-cube L-shape, make up the Soma Cube Puzzle. Easy to make and not too hard to solve. There are 240 solutions Alternatively, take away the L-shape piece and use the other six pieces to make a big L-shape twice the size. A bit harder.

A puzzle with an "Aha!" factor Conways's Curious Cube Six of the pieces are 2" x 2" x 1" blocks. And there are three 1" x 1" x 1" cubes. They can be assembled into a 3" x 3" x 3" cube, but there is only one way of doing it. (John Horton Conway is a mathematician who has produced many wonderful puzzles)

The Fifth Chair Puzzle The four chairs are the same shape, but different sizes. Two small, one medium, one large. Use them all to make a fifth (giant) chair, the same shape as the others. Can you ALSO discover the mathematical principle that makes the puzzle possible? Here are the dimensions of the chairs in mm. Height Width Depth Small 63.0 50.0 39.7 Medium 79.4 Large 100.0 Giant 126.0

Easy to Make, Very Hard to Solve Professor Hoffman's Cube 27 identical blocks of wood (often made in 27 different types of wood) If they were all perfect cubes, 5x5x5, they could easily be packed into a 15x15x15 cube. But these are 4x5x6, so each one can have one of six orientations. A 4x5x6 block has 4% less volume than a 5x5x5 cube, so there are a few small gaps in each layer Here are the three layers of one solution, but it is hard to find