Repeated patterns – no gaps
A shape is said to be tessellated if an infinite number of that shape can be put together with no gaps.
The first time I failed my driving test was when I turned up late (tessellation). I’ve repeatedly failed my test hundreds of times (repeatedly).
A equilateral triangle can form a tessellation.
A hexagon can form a tessellation.
A famous artist who drew tessellations was M.C. Escher
This is M.C. Eschers drawing of Geckos.