Emphasis Preaching Journal

Most major amusement parks feature a ride through a waterway system that eventually leads to a pinnacle. The vessel in which one is riding (the one I remember was fashioned to look like a carved-out log) then plummets down from that pinnacle into a basin of water below. While the vessel of carriage has some freedom to move from side to side along the waterways, its course is continually being corrected as it encounters the walls of the waterway.