A right triangle whose legs are in the ratio 2:1 is sometimes known as a "dom," a name derived from "half a domino." The name was suggested by Andrew Clarke and preferred in an on-line ballot hosted by Livio Zucca.
A dom with leg lengths 1 and 2 has area 1.
It was later found that a double set of didoms will make a dodecagon. This led to the study of so-called domsliced polyforms.