Work­ing as a pro­gram­mer involves think­ing at mul­tiple levels of abstrac­tion. You might be cod­ing a web applic­a­tion, but at any one point it could be data mod­el­ling, present­a­tional markup or low level archi­tec­ture changes. Some­times it is hard to think of some­thing to draw or pho­to­graph. It shouldn’t have to be a real or obvi­ous sub­ject all the time. There­fore I just let my stylus wander and this is what came out.