In one of my higher year 8 classes I set a very open ended task where students could either “work in their books, make a poster or complete a worksheet.” The work they did had to investigate the picture above. That was the extent of the instruction given. One boy, who usually was unmotivated in my lessons, produced a poster with many different examples of different inscribed polygons and clear mathematical labelling of each one. He went on to eloquently explain his work to the rest of the class; however, he made an error in his work – he deduced that because he had drawn an irregular inscribed pentagon, all irregular pentagons could be inscribed. I asked him to investigate this statement but he didn’t see his error and I ran out of time to explain where he had gone wrong.