Investigate the different shaped bracelets you could make from 18 different spherical beads. How do they compare if you use 24 beads?
Can you make these equilateral triangles fit together to cover the paper without any gaps between them? Can you tessellate isosceles triangles?
Draw three straight lines to separate these shapes into four groups - each group must contain one of each shape.
There are lots of answers to this, depending on what questions you choose to ask.