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Bubble pop Nim

By David Shaw, 10 February 2022

Can you be the one to pop the last bubble?

Here’s an old game with a modern twist! Compete with your friends to pop the last bubble.

You will need

• A bubble pop fidget toy. Bigger toys will make for a harder game, but even a little 9 bubble toy will work well.
• Someone to play against

What to do

1. To start, pop all the bubbles and then turn it over so it’s ready to go.
2. Pick who is going to go first.
3. Look at the fidget toy. There will be regions of bubbles that are separated by tall ridges.
4. On your turn, you can pop as many bubbles as you like, but they all have to be from one region. You can pop all the bubbles in a region, but you can also just pop a few. You must pop at least one bubble.
5. After your turn, it’s your opponent’s go.
6. Whoever pops the last bubble wins!
7. After you’ve played one game, flip it over to start again.

What’s happening?

This is a new version of an old maths game called Nim. The rules are quite simple, but the strategy can get difficult. At first, you might just make moves at random, but with a bit of thought you can learn a few tricks to help you win.

At the beginning of the game there are lots of bubbles to pop and lots of moves you can make. Near the end of the game, there will only be a few bubbles to pop and it’s a lot easier to understand what moves are good or bad.

For example, if you empty the second-last region, then your opponent will win by popping all the bubbles in the last region. If you can make your opponent empty the second-last region, you’ll win! one way to do this is give them a board with 2, one-bubble regions.

Here’s one more tip that might help. If there are 2 regions left, try to make them the same size. If you keep copying your opponent, eventually they’ll empty one of the regions, leaving the last region for you to empty.

As you play more games, you’ll spot more winning patterns!

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