This problem is written to stimulate exploration on a geoboard and the hope is that you and your pupils will find further questions to investigate.

The problem is a nice way of raising pupils' awareness of "tilted" squares on a grid and of challenging the frequently-heard cry of "but that's a diamond"! It would be interesting to set children off on tackling this problem, perhaps in pairs, and to listen to the discussion which follows. If, after a short time, no-one has found a tilted square, you could cut out a square from paper, and, after ascertaining from the class what shape it is, you could stick it on the board in different orientations, asking each time whether the shape has changed.

Having found all the different squares, investigating their areas is a natural follow-up which is made accessible by the grid itself.