The Lever is an obstacle that is sometimes encountered in the game.
The Lever is often an obstacle that prevents further progress in the game unless it is found and pulled. It is usually located away from the thing that it controls and often has to be looked for. Sometimes getting to or reaching the Lever can be an obstacle in itself.
The Lever is used for many purposes; for example opening things like gates or starting mechanical devices.
For a list of other types of obstacle see: Hazards