From Wikipedia
Marble Drop is a puzzle game published by Maxis on March 30, 1997.
Players are given an initial set of 42 marbles divided evenly into six colors. These marbles are picked up and dropped by the player into funnels leading to a series of rails, switches, traps and other devices which grow more complex as the game progresses. The aim is to ensure that marbles arrive in the bin with the same color as the marble. Players must determine how the marble will travel through the puzzle, and how its journey will change the puzzle for the next marble. When a marble runs over certain sections of the puzzle, the paths are possibly re-routed or cut-off, temporarily or permanently. For example, if the marble runs over a button, it might activate a diverter that sends the next marble down a different path.