Tim Knowles' tree drawings (top) and my attempt (bottom). I left my drawing out in the rain for a while so the water has made the black felt tip bleed into the paper, an effect which I quite like. After trying this tree drawing I realised that it's harder than it looks, hanging the pens at just the right height is important because if it's too high, it won't draw on the paper and if it's too low, it will just drag and get stuck.