Wiktionary
polyabolo
n. (context geometry English) A polyform made by joining right isosceles triangles edge to edge in various arrangements.
Wikipedia
Polyabolo
In recreational mathematics, a polyabolo (also known as a polytan) is a polyform with an isosceles right triangle as the base form.
The tetrakis square tiling is a monohedral tessellation that fills the plane with 45–45–90 triangles.