This was not one of the assignments I got an idea for immediately. To start, for inspiration, I looked up 'incongruous' (not harmonious, incompatible, inconsistent within itself). Decided on a mobile with the least likely thing to be floating around in the breeze, namely little rocks....I just like making mobiles :)
These daily projects often end up being exercises in problem solving. How to get the thread around the little rocks (a lot of patient knot tying and wrapping). How to hang them from the sticks (jump rings). How to find the balance points and secure the threads in those spots (trial and error and Elmer's).
Because a mobile needs to be seen in motion to be appreciated I made a video of it spinning around for a minute or two. You could hear the birds in the background. It was very restful. But I couldn't get it to work here.