Chalk seems to be my favourite medium to use on the streets these days. I find I keep returning to it as a simple substance that can transform a public space effectively, dramatically, subtly yet remain playful and elicit a generally positive reaction from those who encounter it. Chalk is non-permanent but can remain visible for months despite heavy rains. Indeed some drawings I made over a year ago are still visible as I write. Others I have occasionally touched up like the ‘No entry flowers’ near Hull’s city center. The thought bubbles are fun and quick to do and often I notice other people interacting with them. In fact on Chalk Farm Road in Camden they were barely finished before tourists wanted to pose alongside them whilst companions took pictures with their phones.