The water shooter that shoots from behind and forward in the toilet seat.
The written word. All invention past, present and future depend on being able to describe them and past that knowledge to others. Think about it, no books, no passing on of languages, no documentation of events, no passing on of research, no Chess, no religion, no science.
The wheel, fire, or bacon. Maybe bacon first, then fire, and wheel.
The person who invented money should have unlimited money
My IQ crosses Einstein hehe :)
To cook,imagine eating everything raw
