When we decorate different things, we can use shapes slotted together to make different patterns. People have been making patterns on floors and walls with tiles for thousands of years.
You can place square tiles side by side with no gaps. Will there be gaps if you make a different pattern with square tiles? You can also make patterns with shapes on walls by using stencils. Will there be gaps between a triangle stencil? Circles can be used to make patterns but only with gaps in between.
A learning walk around the school grounds to discover patterns in the brick work or paving stones could follow this clip. Pupils could be asked to predict, then make patterns with other shapes in the classroom such as right angled triangles or rectangles. "Will these shapes leave a gap between them? What patterns can you make with these shapes?" A nice display could result from the children's pattern work.