The Mathematics of Elongo

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robert44444uk
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The Mathematics of Elongo

Post by robert44444uk »

People have asked me, why is there a hexagon at the start of the game, and why are there 13 tiles, 8 wide and 5 narrow in a player's hand? And what about the boma lines?

The two types of tiles (called shields in the game) are a special type of tiling called Penrose P3 aperiodic tiling. Sir Roger Penrose, who lives here in Oxford, is a Nobel-prize winning physicist for his work on black holes, but also a top-drawer mathematician, He found the tiles back in the early 1970s.

By aperiodic tiling, I mean tiling that does not repeat the more tiles you put down. If you think about the common floor tiles which are squares, then the tiles can fill the playing surface without any gaps, in a repeating pattern, as is the case with games like Carcassonne and Marram. This type of tiling is periodic.

The Elongo tiling can also fill the playing surface with no gaps, but only if certain rules are kept.

One of those rules is the fact that you need a "seed" at the start of the tiling to enforce aperiodicity, otherwise the tiling could become periodic, which would not make for interesting shapes. There are an infinite number of these seeds, but there are 8 small ones where the seed is made up of 7 or less tiles. The simplest ones have three tiles, both create a hexagon shape, one with two wide tiles and one narrow one, and the other with 2 narrow tiles and 1 wide one. Others have nicknames, like the 4-tile crown, and two different 5-tile shapes called stars. These shapes are all created naturally as the game goes on. In the design, I opted for the simplest shape, the hexagon.

You may have heard of the golden ratio, called phi, which appears in art, and in nature. Think of a Nautilus shell or the Fibonacci sequence. Mathematically it is 1+the square root of 5, all divided by two, which works out at approximately 1.618033.. At the heart of the mathematics for Penrose tiling is the 5-fold symmetry that you will see in the game when you lay 5 wide tiles in a circle, The golden ratio is the ratio of tiles - the ratio of wide to narrow - that is needed to enforce the filling of the playing surface. In the design of the game, I mimic the golden ratio by choosing a ratio of 8:5 which is 1.6, quite close to 1.618033.. Given that the game is short, this approximation is acceptable. Hence 8 wide tiles and 5 narrow ones.

Penrose tiling is also special for another reason. 5 is a magic number so pentagon shapes appear, but so can four-sided shapes and 3-sided shapes, which is why you see bomas which enclose 3-, 4- and 5 land patches.

The final rule that enforces aperiodicity relates to the way you can lay tiles to join each other. This is why you see two sets of dotted lines, one black and one brown, on the tiles. This restricts the ways you can join the tiles. I designed the lines so that they could join up to create the bomas creating a different set of patterns other than the land and its colours.

I hope this provides some explanations to those who were interested.
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Spiegel428
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Re: The Mathematics of Elongo

Post by Spiegel428 »

That’s very interesting! Thanks for sharing.
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Barberserk
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Re: The Mathematics of Elongo

Post by Barberserk »

Given all you said above, is it possible to have a semi-transparent grid on the edges of the map, to be able to see what tiles can fit, or would the lines of potential additions make everything look too messy? I wish some guiding lines existed, so you can plann 2-3 steps ahead more easily.
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kamaboardgames
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Re: The Mathematics of Elongo

Post by kamaboardgames »

Very interesting post!
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robert44444uk
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Re: The Mathematics of Elongo

Post by robert44444uk »

Barberserk wrote: 27 November 2025, 15:36 Given all you said above, is it possible to have a semi-transparent grid on the edges of the map, to be able to see what tiles can fit, or would the lines of potential additions make everything look too messy? I wish some guiding lines existed, so you can plan 2-3 steps ahead more easily.
We thought about it, and you are right, it would look very messy because you would need two semi-transparent shapes, each in two orientations to show all the possible joins, and that is just for joining to one tile. Now multiply that by all of the tiles on the peripheral, and the result is confusing and messy. There are only two types of tiles, and all tiles of the same shape fit the same places, even though they have different colours. Generally, any tile can fit to any other edge, except where the game shape has concave areas, and then it gets complex.

If I create a block, so that an opponent can no longer lay a tile to enclose a patch that they control, out of niceness I tell the player that they should take that man back. They tent to get miffed about that, but laying blocks is an integral strategic move in the game!
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Barberserk
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Re: The Mathematics of Elongo

Post by Barberserk »

Sadly you have to be "fun-spoiler" as many people see this distructive aspect of the game, in order to win. Yes lots take offense in it.

I don't know if it is off-topic, but instead of creating a new thread, I think I can ask here. Is Elongo prone to card/tile memorization like Carcassone is? Are the tiles fixed, and their combinations finite? I really hope there is a RNG behind it and the tiles you get can't be predicted... I don't want to turn into a human robot in order to beat experienced players, that know what tiles we are getting next.
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Jellby
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Re: The Mathematics of Elongo

Post by Jellby »

robert44444uk wrote: 27 November 2025, 12:10 Sir Roger Penrose, who lives here in Oxford, is a Nobel-prize winning physicist for his work on black holes, but also a top-drawer mathematician, He found the tiles back in the early 1970s.
He also contributed to popularize (together with his father, according to Wikipedia) the shape in my avatar (https://en.wikipedia.org/wiki/Penrose_triangle).
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zhuoyouji
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Re: The Mathematics of Elongo

Post by zhuoyouji »

恕我直言,这个规则书简直是一场灾难。这么有趣的游戏题材,却被搞的这么复杂和混乱。明明可以做一个有趣的家庭桌游,却非要硬着头皮上强度?
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robert44444uk
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Re: The Mathematics of Elongo

Post by robert44444uk »

zhuoyouji wrote: 30 November 2025, 22:26 恕我直言,这个规则书简直是一场灾难。这么有趣的游戏题材,却被搞的这么复杂和混乱。明明可以做一个有趣的家庭桌游,却非要硬着头皮上强度?
I think this translates as:

Forgive my bluntness, but this rulebook is a disaster. Such an interesting game concept has been turned into something so complicated and chaotic. It could have been a fun family board game, but instead, it's been forced into a gruelling, demanding format.

You are forgiven! The rulebook could be simpler, I agree, and maybe I shall rewrite it. The game is actually demanding to play well - I wanted to create a game where chance is as small an element as possible.

I have given the tiles of my prototype to a 5 year old, who delighted to create shapes and patterns, including stars and turtles (that was a favourite). Intuitively she was able to create parcels of different coloured land and place animals on it and boys and warriors to tend to them. So as a one player toy, you can throw the rulebook away use the tiles and just let a child play!
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robert44444uk
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Re: The Mathematics of Elongo

Post by robert44444uk »

Barberserk wrote: 29 November 2025, 14:44 Sadly you have to be "fun-spoiler" as many people see this distructive aspect of the game, in order to win. Yes lots take offense in it.

I don't know if it is off-topic, but instead of creating a new thread, I think I can ask here. Is Elongo prone to card/tile memorization like Carcassone is? Are the tiles fixed, and their combinations finite? I really hope there is a RNG behind it and the tiles you get can't be predicted... I don't want to turn into a human robot in order to beat experienced players, that know what tiles we are getting next.
Good question!

The 102 tiles are fixed, and the total combinations is hence finite, but enormous. A.I. suggests the total possible combinations is of the order of 10^26, given the numbers of each tile. that is 100,000,000,000,000,000,000,000,000 For all intents and purposes, therefore, todays computers cannot compute all permutations.

Tiles are randomly distributed from the 99 tiles remaining after the hexagon tiles have been selected. The hexagon tiles are also randomly selected from a slightly small number than 102, as the all-one-colour tiles are not used in the hexagon.
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