I thought it would be amusing to make a giant camera that looked like a toy prop but actually took pictures.
The internals of this camera are operated by a Raspberry Pi Zero, powered by two 18650 batteries. The camera takes a picture, sends it over wifi to another Raspberry Pi connected to a large display, shows the image for a few seconds, then stitches the image into a mosaic. Users would be encouraged to guess what the mosaic was working to become as it grew throughout the event.
Mosaics are usually built all at once. You have a target image, a collection of source images, and you iterate through possible combinations for the best mosaic. Instead, I started with a target and no source images, so as pictures were taken by the camera and my collection of source images grew, I'd find the best place to put each image into a predetermined target image. I wrote the algorithm in Python leveraging the OpenCV library.
All of the source code, including the reverse mosaic algorithm, can be found here.