Cylindrical sundial

Portable cylinder or pillar sundials are also called poke dials or shepherd's dials, because they used to be carried in the pockets (pokes) by shepherds. Another name for this dial is the traveler's dial. The dial is in the form of a cylinder with the gnomon attached to a movable top. The hour lines are in the form of curves inscribed or printed on the cylinder. To tell the time, the gnomon is set over the vertical line of the day and the time read off where shadow of the point of the gnomon falls on a hour line. The pillar sundial is an altitude dial. (text source: https://www.qwerty.co.za/sundials/types/poledial.html)