How does a 3 way lamp work to provide different levels of brightness?

A 3-way lamp works by having a special socket that can accommodate a 3-way bulb with two filaments of different wattages. The lamp has a 3-way switch that allows you to turn on one filament for low brightness, the other filament for medium brightness, and both filaments for high brightness. This way, you can adjust the light output to three different levels by toggling the switch.