Absolute Genius competition: How was the Velcro fastener invented?
There are less than two weeks left to enter Newsround's Absolute Genius inventions competition.
To get your brains ticking, Joe's been finding out who came up with the idea of the Velcro fastener - and how.
The Velcro fastener was created in 1948 by Swiss engineer George de Mestral.
He came up with the idea while out walking his dog and his clothes became covered in small sticky seeds from the burdock plant.
Under a microscope, he saw the seeds had tiny hooks to grip on to his clothes - and that's what he based Velcro on.
It's now used on loads of different things, such as coats and shoes. Nasa even used it on their space shuttles!