## Introduction: Pyramid Puzzles

When I left the robotics competition this weekend, I had a car full of these large plastic balls. I have been wanting to have them since I first laid eyes on them. I just knew that they would make a great puzzle.

Every year the people at F.I.R.S.T. come up with a new and different game for the robots to play. This year, the game involved the robots collecting and shooting these balls into a hopper. It seemed a shame to let these go to waste after the season was over.

You can do the same thing on a smaller scale with practice golf balls. I have tried for years to make these out of ping pong balls but just could not figure out what kind of glue could stand up to teenage abuse.

## Step 1: Materials:

Balls with holes--20 for the small puzzle, 35 for the large puzzle

Zip ties--lots of them

Scissors--strong enough to cut the ends of the zip ties

Plyers--to pull the zip ties tight (optional if you have strong hands)

## Step 2: Notice the Pattern of the Holes

I noticed that the hole pattern on the balls was different on different parts of the ball. It would be a good idea to check yours before you start. You want the balls to line up right or the puzzle will not work well.

My balls had a seem around the middle where the 2 pieces of plastic were joined. The holes around this equator were arranged differently than the holes at the north and south poles. At the poles I had one hole surrounded by 4 holes. This is the set of holes I choose to work with.

The holes on my practice golf balls were arranged in clusters of 4. You could use 2 opposite clusters to connect them.

## Step 3: Making a Straight Piece

I needed 2 puzzle pieces made out of 4 balls each. The balls needed to form a straight line when zip tied together.

I used the center hole and one of the surrounding holes to slip the zip tie through. Don't pull the tie tight yet. I repeated this process until I had 4 times joining the 2 balls. When I had all of the corresponding holes connected, I used the plyers to pull them as tight as I could.

I kept going until I had 4 balls connected. Then I trimmed the tails of the zip ties.

## Step 4: Rectangular Pieces

This puzzle also requires 2 pieces that are made from 6 balls. I started by making 4 straight pieces of 3 balls each.

By laying 2 of the straight pieces next to each other, I could figure out which holes to use in order to join then together. I used 3 zip ties--one for each pair of balls.

These 4 pieces make one tetrahedral pyramid. I will leave the puzzle for you to solve. If you get frustrated, it is not hard to find a solution on line. Google "pyramid ball puzzle".

## Step 5: Side 5 Pyramid Puzzle

This puzzle makes a bigger pyramid--5 balls on each edge. I joined the pieces in the same manner as the previous puzzle but you do have to be careful when you make the angled pieces that you get the angle right.

## Step 6: Side 6 Pyramid Puzzle

This puzzle has 2 pieces that are 6 balls long. There are 2 pieces that are 2 by 5 rectangle and 2 pieces that are 3 by 4 rectangles.

## Step 7: Another Side 4 Pyramid Puzzle

This puzzle has 2 pieces that are 4 balls long and 4 pieces that are 3 balls long.

## Step 8: Side 3 Pyramid Puzzle

This tiny one is easy enough for a puzzle beginner. This one only requires 10 balls.

## Step 9: Side 4 Pyramid Puzzle

This puzzle has 2 pieces that are 4 balls long. The other 2 pieces are 2 by 3 rectangles.

## Step 10: Yet Another Side 4 Pyramid

This one has 2 solutions--one is a pyramid, the other is a roof shape.

## Step 11: More Puzzles

In the picture above, one of the pieces uses 5 balls--this is the only piece that I made that is not flat.

This is where I ran out of balls. Until I can get some more, I have to resort to the smaller golf balls size.

We will be using these puzzles with the kids at the elementary school--according to my son, we don't have room at home for 'puzzles of this magnitude.' I need a way to mark the pieces of each puzzle so that I can store all of them in one large clothes hamper and have the kids able to sort them without my help. Any ideas?

Check out www.robspuzzlepage.com if you want more ideas for puzzles. I don't know Rob but his puzzle collection is amazing. He has puzzles that I used to own but forgot about years ago.

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