As the motor turns, the mask rotates, causing the striped pattern to alternately block and transmit the light beam.
"Any of more than a dozen species of snakes (genus Thamnophis, family Colubridae) with a striped pattern that resembles a garter: usually one or three longitudinal yellow or red stripes, with checkered Blotches Between."
The tight layering of the CARDS creates a brilliant striped pattern, and, as Shaheen notes, the different shades of yellow resemble wood grain.