9 to 12 year olds
On a 3×3 grid, if you can paint two squares in blue and the rest yellow, choose a shape and find all that are different from it.
We will consider that they are equal if they correspond by a rotation or a symmetry of the one you chose at the beginning.
For example, drawings A and C are different, but drawings A and B are the same. Also C and D represent the same configuration (they correspond by a rotation).