Use your keyboard numpad (this only works on a computer or a device that has a physical keyboard). Each number corresponds to a segment (see the Info menu), pressing a button makes that segment toggle between off and on. Pressing 4 makes all segments turn off, pressing 6 makes all segments turn on.
This was originally meant as a quick school project, I decided to expand it a bit more here. I used GIMP to edit the sprites for the Info and Back buttons and menus. The segment PNG is from Wikipedia.
