This is a full page illustration for Communications of the ACM magazine about two fields of computing science, Artificial Intelligence (AI) and Human Computer Interaction (HCI), and how they overlap in the design of a system for machine language translation.
Although it was quite a technical piece, the core theme was actually quite simple - two things working together on language translation. I started thinking harnessed horses, rowers, dancers etc. but once I hit on a tandem bike I knew that could work.
The sketches below show the conceptual process. Once you have something to draw you're up and running! Starting with the idea of the tandem wheels reading as eyes on a face with a digital brain and mouth emitting a stream of words and letter forms. Didn't like the brain so removed it and added figures. Didn't like the mouth so got rid of that. So it was then a question of finding a nice way to unify the tandem and letter streams.
As the wheels were moving it seemed they should be generating the language so I tried a few ways to show that. Once I had them working in a shape I liked I added a little brain above one figure to identify it as AI and cogs above the other to identify it as HCI.