When I was preparing What To Do I drew lots and lots of domes, in pencil and biro and colour-coded felt-tip pens. The fifteen domes above are cut out from the script I used for the talk itself, where I’d drawn them in margins to remind me what to copy on the flip-chart as I went along. The different colours are to show me which parts to draw in what order, and they correspond with sentences in the script underlined in the same colours.