A screw-propelled vehicle is a land or amphibious vehicle designed to cope with difficult snow and ice or mud and swamp.

Such vehicles are distinguished by being moved by the rotation of one or more auger-like cylinders fitted with a helical flange that engages with the medium through or over which the vehicle is moving./wikipedia

Modern vehicles called Amphirols and other similar vehicles have specialised uses.The weight of the vehicle is typically borne by one or more pairs of large flanged cylinders; sometimes a single flanged cylinder is used with additional stabilising skis.

These cylinders each have a helical spiral flange like the thread of a screw. On each matched pair of cylinders, one will have its flange running clockwise and the other counter-clockwise.The counter-rotations cancel out so that the vehicle moves forwards (or backwards) along the axis of rotation.

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