Numbers as symbols – and the perception of form

A study in numbers as symbols

Video. 2024

A video of a 30mph speed limit road sign with the number 30 rotating within the circular sign. The figure 30 in the sign has been animated digitally.

This concept occurred to me spontaneously when I looked at the sign (Having said that, I’ve walked past this sign many times over the past few decades and the idea has never occured to me before – more on that later). The sign is in Market Drayton, Shropshire, where I grew up.

One of the points that the video is hopefully making is about the nature of the shapes of numbers (and by association, of letters too). I’m interested in the fact that the shapes of numbers (and letters) are to a large extent random. You can understand why the number one is represented by the shape 1, which is essentially the simplest possible mark that can be made to represent the presence of something, and why zero is represented by 0, which is possibly a symbol that visualises an empty space. But why is 4 the shape that it is, or 5,6,7,8,9?

Bearing this interest in the shapes of numbers in mind, one of the features of the video is way that it emphasises the changing shape of the numbers as they rotate. When the 3 and the 0 are on their sides they no longer look like the number 30 viewed sideways but as distinctly different shapes – especially the 3. The 3 stops being a 3 and starts becoming a mysterious symbol. This phenomenon works particularly well with the numbers 3 and 0 because the shapes of these numbers are more or less symmetrical about a horizontal axis through their centres. It wouldn’t work so well with, say, the number 47, where the brain would probably have a lot more difficulty seeing the digits as nothing other than the 4 and the 7 at unusual angles.

perception of form and numbers as symbols

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