... A sundial with a vertical pointer (" gnomon ") will indicate noon correctly when its shadow points north or south. ... Cut the paper along the marked line: one half will serve as base , the other will be used to construct the gnomon . In the gnomon part, cut away the two marked corners. ... With the page folded in its middle, cut out along the curved line , cutting a double thickness of paper in one cut. ... In cut (4), the fin of the gnomon was separated from two pieces with curved outlines. ...