Use a broken speaker, bits of wire, and tape to prepare a coneless voice coil driver, then use it to generate standing waves on a sheet of metal, making sound visible.
After taking a flower arranging class in college, my wife likes to whip up nice flower arrangements for friends, parties, weddings, and in this case today, funerals too.
Make a chair that's comfortable, looks good, reclines, disassembles for compactness and portability, and can be made from just a single sheet of plywood.