Each layer of the egg puzzle has some holes, which can go straight down, curve and go down or only go part way through to the other side. Each layer also spins around a center pole. The goal is to get a ball through all the layers of the egg. In the default position (slices aligned to form nice egg shape),the ball can only go through one layer at a time. The player inserts a ball into the top layer, twists that layer to the right or the left, until the ball falls through to another layer. (Metal balls work best because you can feel and hear them fall through the layer.) Twist the each layer to get the ball down to the next layer, until the ball rolls out of the bottom layer. Some holes are 'traps' and do not let the ball pass through, if this happens, invert the puzzle and go back up a layer to try again.
blue styrofoam insulation (2 inch foam insulation board)
a sharpened wood pencil
a thin-bladded, serrated knife (pumpkin carving knives work well)
a hack saw (optional)
drill or cork hole cutter
acrylic craft paint
small metal ball bearing (a small 'steelie' marble)
Step 1: Overview
The hole at position B has a variable path. Turn the top-counter clockwise until both B holes align and the ball falls to layer 2. Turn layer 2 counter-wise and the B holes will align, dropping the ball to layer 3. Layer 4 has a trap. If you turn layer 3 counter-clockwise, hole B will align with a grey hole at radius B. This hole only goes halfway through the layer and the ball is trapped. If layer 3 is turned counter-clockwise, the ball will fall into the while B hole on layer 4. Rotate layer 4 clockwise and the ball will roll through hole B in the bottom layer, and out the side of the egg.
Step 2: Make the Egg Shape
Step 3: Slice Egg Puzzle
Prepare your egg for slicing. Carefully push a sharpened wood pencil through the center of the egg, this will be the center axis. You can start the hole from both ends and meet in the middle. Watch your fingers - a pencil point stab hurts :-)
Remove the pencil and evenly slice your egg into 4 or 5 layers. Each level should be at least twice the diameter of your ball. three or four is better. Do not copy my poor slicing, keep your slices even, and your puzzle will work more smoothly than mine. Use a hack saw or your serrated knife. If your edges are rough, lightly sand the flat sides of each slice.
Step 4: Cut the Holes for the Steel Ball to Roll Through
Plan out your holes, you can use the overview figure as a model. Some things to remember:
In the default egg shape, a hole should drop only one level (slice). Holes should line up with a lower level only when you rotate a level.
Keep at least a hole's width between holes on each level, so you have a structurally sound egg.
Decide how many 'traps' you want to set.
Once you have a plan, cut or drill your holes. I found a cork cutter in the garage and it worked great on blue styrofoam. It's basically a metal tube that is sharpened on one end. Press and twist it to cut a hole. You can cut holes straight down or on a diagonal. You can also cut 'elbow' holes, cut at an angle from both the top and the bottom until the holes meet form a 'bent hole'. Use a small, round file to clean up the holes.
Traps are holes that only go partway through the level, lit little pit traps.