Maya and MatthewӬ from Beechwood ParkӬ School wrote in to say:
It took Matthew three shapes to guess my rule. My rule was that the shape had to have a point.
Oliver also from Beechwood ParkӬ added his rule:
Anything with one side or four sides but not rectangles.
I am quessing that probably many children got involved in this activity with or without their teacher but perhaps they did not see that they had a "solution". It's always interesting to hear about any response to the activities, even if there is no "solution" as such.