It is actually an inclined plane that winds around itself. A screw has ridges and is not smooth like a nail. Some screws are used to lower and raise things. They are also used to hold objects together. The girl in this picture is taking a lid off of a jar.
Jars use simple machines to hold the lids on the top.
When you turn the lid, it raises or lowers. Use the marker to outline the diagonal side of the triangle. Now place the paper face down on the table. Place the pencil on one of the short sides of the triangle. Wrap the pencil around the triangle.