Young professionals tested the Workshop “Persistence of vision” at Fablab Karlsruhe. In this workshop LEDs are used to write a text or images on a phosphorescent surface. What we need to make the text visible is a rotating drum, coated with a phosphorescent film and illuminated from the inside with light using LEDs. As controller the ESP8266 is used, which is an Arduino-like programmable platform with WLAN capabilities. The workshop participants had fun soldering the different electronics components as well as programming the microcontroller. In the end everyone was fascinated by the illuminated text appearing on the phosphorescent film.