 After the introduction of decapoint, Braille gave assistance to his friend Pierre-François-Victor Foucault, who was working on the development of his Raphigraphe, a device that could emboss letters in the manner of a typewriter.Foucault's machine was hailed as a great success and was exhibited at the World's Fair in Paris in 1855.Although Braille was admired and respected by his pupils, his writing system was not taught at the Institute during his lifetime.