I have just finished teaching one of my absolute favourite sessions in a school. Introducing the children to John Baldessari who himself was a teacher, describing seeing no difference between his teaching and making. His practice is about shaking people up and encouraging them to reconsider their ways of seeing. I challenged our young artists to do the same today. Many of his works play with the erasure of identity and disguise. Faces in his photos are masked by coloured dots and Although they can at first seem forbidding, the mysterious absences in his work enable participation, as we have to find our own ways of uncovering the hidden. The children used this idea to create their own pop-up worlds and played so well with the concept of 'not knowing'. We took it in turns to interpret our friends' characters and worlds and I have to say they were so incredibly perceptive and imaginative I left beaming from ear to ear.