Lichtenberg figure electrical discharges. Footage of a piece of cardboard being used to produce Lichtenberg figures of electrical discharges from a high-voltage generator. on wet cardboard. The first step is to apply salt water to the cardboard surface. Electrodes are then attached and the generator turned on. The clip is then shown as a time-lapse sequence, first speeded up 10 times, and then speeded up 80 times, returning to a speed of 10 times at the end of the clip. The high voltage causes electrical sparks to burn patterns in the cardboard, showing the path taken by the electricity. This pattern is known as a Lichtenberg figure.