Introduction to programming by building coral

executive skills

Think logically, think in steps and think ahead and of course: strike in time. REEF is a cool puzzle game that is harder than it initially looks.

REEF is a puzzle game for two to four players. Each player builds his own coral. That coral grows in both width and height and can score points each time.


The patterns may also be made mirrored, so good spatial insight can earn you more points.


But the big challenge of this game is in the planning. This is because all cards have two sides: the top part shows the coral you may take. The bottom part shows the pattern that earns you points. You always have to place the coral from the top of your card on your board first. Then you check if you match a pattern and you may score points.

So you can NOT play a card just to score a pattern and that makes this game challenging.

Start with coral and cards

Each player gets a player board, three cards and three coins of 1. In the middle of the table you put a pile with the rest of the cards. Of these, you turn three open and also turn open (and put on the pile) the top card of the pile. The person who has the starfish on her player board is the starting player.

You may always choose one of these two actions:

A. Pick a card from the market

You take one of the three face-up cards and put it in your hand. You can have a maximum of four cards in your hand. By the way, do you want the open card that’s in the pile? You can, but then you put a 1 coin on one of the three face-up cards. You put it on the card with the lowest value.

B. Play a card

When you play a card from your hand, take the coral shown on the top section. Then you look at the pattern on the bottom section. Do you have that on your game board? Then you score the number of points shown on the card. It is also possible that you have the pattern on your board several times. In that case, you also score points several times.

Going up!

Sometimes there is a pattern on the card that says 2 or 2+. That means your coral must be 2 high or at least 2 high. The colour on the pattern is always the colour you see from above. So it’s best to start with yellow and put a green coral on top of that. By the way, your coral should not be higher than 4 levels.

An if-then construction and a sequence of steps. It’s like programming!

For example: the pattern on the right card is worth five points. For that, I must have built two red corals of two high next to each other. For that, I must first play and build card 1 and then card 2. Before I earn five points, I am three rounds further.

Computational thinking is something children learn through games such as REEF, but also through 111 Ants, for example. Because like programming, with Reef you sometimes run into deadlock: you need the coral from card A to make the pattern on card B. But the coral from card B is exactly what you need for the pattern on card A. Aaarrrchh! You have to puzzle cleverly to get out of that!

Practice metacognition, working memory, organisation and goal-directed behaviour

What makes this game extra fun is that it also looks really cool! The coral reef theme is nicely done. The pieces of coral fit together easily and each structure looks different. You can debate whether an ecological subject like this should be done in plastic…. but it makes the game very sturdy and gives very long playing pleasure.


Another wonderful coral-themed game is Coral. A totally different game mechanic: in this game, you build coral. Coral is a shorter game and can also be fun to do in teams. Read my review here.


General information about REEF


  • number of players: 2 – 4 players
  • time: 30 – 45 minutes. The game ends when a coral colour runs out. This can be faster if many cards of the same colour are turned over and everyone starts building that colour.
  • from: 8 years
  • price: around € 35 (Dutch price)
  • download the quickrules

This review was updated November 2023. You will find affiliate links in the text. When you purchase the game (or anything else) through these links, you support this website and the work of Pen & Pion. 🎲🧩♟️


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