A list of what I think are the most useless inventions are:
1) solar-powered flashlight
2) water-proof sponges
3) 2-sided playing cards
4) toilet-paper dispenser on head (as seen in picture)
5) submarine with a sunroof
6) left-handed pencil
7) air conditioning on a motorcycle
8) fire-proof cigarettes
9) inflatable dartboard
10) black highlighter pens
----
Feel free to add you own!!
A list of what I think are the most useless inventions are: