8 and 9 year olds.
I was asked to create a lesson that involved geometry. I had taken a tessellation lesson in the passed, but recall it being difficult to add colour. So today I followed a similar lesson but used coloured paper, rather than painting the shapes. This was just as lengthy and trying for the children, but I think the result is crisper.
Here is the original lesson with links to Escher and Holly's blog.