# Easy to Make, Hard to Solve: Two Puzzles

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## Introduction: Easy to Make, Hard to Solve: Two Puzzles

Here are two puzzles using materials you may have already laying around; they may be easy to make, but hard to solve!

The first puzzle is the Shackles Challenge. You'll need 6' total of rope or string and a partner. In this puzzle, you and your partner start "shackled" together, and must figure out how to separate without removing the shackles.

The second puzzle is the Balancing Nails puzzle. You'll need 7 nails- common nails with a wide head- and something sturdy to drive one of the nails into (such as a scrap piece of wood at least 1" thick). This puzzle requires creativity to balance 6 nails on the one upright nail head. Can you solve it?

## Step 1: Shackles Challenge

This challenge is a partner problem solving exercise. It will require collaboration and creativity.

Take your 6' section of rope/string and cut it in half. With both sections, tie an adjustable size loop on each end. I tied a simple overhand knot for each loop- it is not weight bearing or meant to be a permanent knot, but it can be slid along the rope to adjust the loop size as needed.

Start with your partner in the position shown in the picture above, hands through the loops (towards their partner). The goal is to figure out how to separate your shackles without ever taking any hands out of the loops. You may adjust the loop (size) around your hands as needed, but can do this without taking your hands out of the loops.

For safety reasons, and because it is not necessary to solve the challenge, you should not climb through/under/over the rope, nor should it wrap anywhere close to either person's head or neck.

Hints:

1. To solve this challenge, no crazy contortions are necessary; in fact, both participants can sit or stand in one spot while untangling the Shackles.
2. I mentioned you MAY adjust the loop sizes, without taking them off the hands. The solution is easier if you make just one loop of the four a bit bigger so that something can pass through that loop- but that something is not the hand, so keep that in the loop.

## Step 2: Balancing Nails

The puzzle is to figure out how to balance all 6 loose nails on the head of the upright nail, without letting any nail touch another surface.

You'll need 7 nails with a large head and something to place one of the nails upright into. I used a scrap piece of wood (I recommend at least 1" thick"). You may also place it into any sturdy permanent surface (like a table top), given you don't mind a nail sticking out of that surface. Only drive the nail a little ways in; try to leave at least 4" above the surface. After placing a nail upright into the piece of wood, you have 6 loose nails left.

Hints:

1. I recommend arranging the 6 loose nails in some sort of structure that you can lift onto the head of the upright nail.
2. There is no gluing, hammering, or any other permanent method of attachment allowed.

Solutions to both puzzles are below. If you haven't figured it out yet after multiple attempts and significant effort, keep scrolling down to reveal the answer.

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## Step 4: Solutions: Shackles and Balancing Nails

Shackles:

As shown in the picture, pass a bight (a bend of rope) through one loop and then over the hand. Once that bight of rope goes over the hand from palm to the back of the hand, the shackles are separated.

Balancing Nails:

Lay four nails perpendicular across one nail, then add the 6th nail on top of the first nail. Lift up the whole structure by picking up the bottom and top nail together; when you lift it up, the heads of the middle 4 nails should catch on the nails that are on the bottom and top. Simply place/balance it on the head of the upright nail and let go gently. The nails should stay balanced as in the picture.

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## 3 Discussions

Ah yes! The old balancing nail trick. I love it!