What inventions are there that have no practical use on a whim?

Multifunctional family bicycle, the design inspiration of family bicycle comes from small family disputes. Because the youngest daughter in this family likes to go out to play, the eldest son likes to ride a bike, but his father only likes to drive a car, and his mother only likes to sit by the sewing machine and mend clothes. So with the efforts of the whole family, such a multi-purpose family bike was invented. At the beginning of the design, the designer wanted to apply for a patent and mass production, but because of the strange shape and heavy fuselage, everyone was distressed and laughed at, and finally the invention was eliminated.