A circuit is displayed. The circuit is a rectangle with a line through the middle. There is an unlit lightbulb on top, an open switch on the middle line, another open switch on the bottom-most line, and a battery on the right side between the topmost and middle horizontal lines.
The switch on the middle line closes, and the lightbulb turns on. It opens again and the lightbulb turns off. The switch on the bottom line closes, and the lightbulb turns on. It opens again and the lightbulb turns off. The switch on the middle line closes, and the lightbulb turns on. The switch on the bottom line closes, and the lightbulb is unaffected. The switch on the middle line opens, and the lightbulb is unaffected. The switch on the bottom line closes, and the lightbulb turns off.