In our first month of engineering, we created our own stools. These were made out of 2x3" wood planks. We scaled out the dimensions our stools would need to be, including the difference that the slicing of the wood would make itself (1/8"). We then drilled pilot holes and screwed them in place, then unscrewed them so we could connect them with wood glue to hold them in place.
Through this project, I learned how to apply mathematics to build actual physical structures, whereas before all I could apply it to is finding the height of something that has already been built. This application of different mediums to create something - wood working, mathematics, chemistry (how wood glue binds differently) - gives a very large feeling of accomplishment.