Tetractys

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This pattern of ten dots arranged in four rows to form the outline of an equilateral triangle, is known as a tetractys. Some call it a decad, which seems somehow less appropriate to me.

The word Tetractys comes from the Greek root Tetra- (four rows), whereas the word decad — as in decade — means ten.

To some, it's a magical symbol. To others, it is the basis of a special kind of poem. Mathematicians see it as a representation of the triangular number, 10, while (some) musicians see it as a representation of the pentatonic scale. Yet others see it every time they go bowling.

A tetractys poem has a special structure. You might call it the Brits' answer to a haiku:

First line - 1 syllable Second line - 2 syllables Third line - 3 syllables Fourth line - 4 syllables Fifth line - 10 syllables

On Scafell Pike

Stone upon huge stone piled - a devil's cairn

Antlike I clamber towards a grey sky.

by Ray Stebbing

In poetry a form which consists of, initially, four lines, the first having 1 syllable, the second 2, the third 3 the fourth 4. These are followed by a fifth coda line containing 10 syllables (the sum of lines 1-4). the whole is centred to form a triangle

Also quite common is the double tetractys where the first tetractys is followed by a second reversed, so that the whole forms a diamond shape.

An example of the latter - my first and so far only attempt in the form - is below

stars
planets
asteroids
and nebulae

Litter this galaxy, this Milky Way

The sky's so crowded, I wonder – don't you -

in cosmic terms
Who will care
what I
do?