Steamroller

A steamroller is a type of heavy machinery which consists of a large tractor and a heavy cylinder that sits in front of it and functions as the front wheel. Steamrollers are generally used in paving roads, to flatten out the surface.

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Steamroller is also a term used by smokers of cannabis to describe a type of pipe that consists of a hollow tube with both ends open, and a bowl on one side near one end. It is presumably called this because of its resemblance to the front wheel of the piece of machinery. A steamroller is used by filling the bowl with cannabis, putting one's hand over the end of the pipe nearest the bowl, putting the other end in one's mouth, lighting and inhaling until the chamber is filled with smoke, and then removing one's hand from the end and quickly inhaling the collected smoke.