Please watch this video from BBC Bitesize it explains what tessellation is.
https://www.bbc.co.uk/bitesize/topics/zbtp34j/articles/z7b66v4
Do you remember the shape tiles we used in class. Lots of coloured shapes had to be fitted together to make a pattern.
Topmarks has an online model. You can use the tools at the side to rotate the 2-D shapes to fit.
Go to Topmarks
https://www.topmarks.co.uk/maths-games/5-7-years/shapes
Scroll down to find Tessellation Creator and Pattern Shapes. You will enjoy making patterns and moving the shapes to fit together.