Braille are devices that can be attached to conventional computers (or built into handheld computers designed for visually impaired individuals) and that continuously convert screen output into braille form.

Braille Displays

Blind computer users can use braille displays to access info on a computer screen. Braille displays are able to do so by electronically lowering and raising different combinations of nylon pins or metal on its built-in brain cells. 
Brain Displays, which are refreshable, are able to display 80 characters from the screen.

Iguess parallel lines

Answerimage;