What is the floating button on the elevator for?
Have you ever wondered why the buttons in the elevator always have small floating dots?Video: The process of creating a Braille system for the blind
Braille is a braille system for blind people with each word made up of 6 points, arranged in a rectangular frame of two columns, three lines.10 youngest inventors in the world
Most of the inventors below have published their inventions at school age to school.