Sunday, April 04, 2021

What do you call a three-pointed geometric figure?

In the east end of Toronto, there an area called Thorncliffe Park. It is a low income, immigrant-heavy neighbourhood, currently a nexus of COVID-19 cases in the city, and it is dominated by two high rise buildings which are composed of three wings radiating out from a central core. The buildings are quite distinctive, and clearly visible on Google Maps.

It got me wondering, though, what is the name of that shape: three lines radiating from a point at 120° to each other.

It's the kind of thing that really ought to have a name, whether in mathematics or in design, architecture, art, or some other pursuit. My first thought was a "three-pointed star", but it's not really a star (the three-pointed Mercedes logo is much more star-like).
Well, it seems like I am not the only one wondering. The geeks at StackExchange are on it too, but there does not seem to be a recognized name for this very basic shape. Suggestions include "Y-shape" or " inverted Y-shape", " tri-point", "triradius", "caltrop", "forked cross", "inverse hexagon", etc, etc, although none of these suggestions enjoy universal approval.

It looks like the best bet may be "forked cross" (also known as "crucifixus dolorosus", "furca", "y-cross", "ypsilon cross", "robber's cross" or "thief's cross"), which even has it own Wikipedia entry, although I am not totally happy with this because of the longer downward-pointing line (like a capital Y), its inverted orientation, and its lack of rotational symmetry.

Anyway, just idle speculation. There are probably more important issues in the world.

No comments: