It is a conventional wheel with a series of rollers attached to its circumference, these rollers having an axis of rotation at 45 ° to the plane of the wheel in a plane parallel to the axis of rotation of the wheel.
It is a conventional wheel with a series of rollers. These rollers are attached to its circumference. These rollers were having an axis of rotation at 45 ° to the plane of the wheel in a plane parallel to the axis of rotation of the wheel. Its circumference is these rollers.