Drawing a Flag Using the Pen Tool
This video shows basic usage of the pen tool for drawing a grid-aligned flag icon in IcoMoon's vector editor.
After drawing the first curve, it is dragged while holding Alt/Option in order to make a duplicate of it. This works when dragging the path itself. Dragging control points of the path while holding Alt has a different effect and won't make a duplicate. You could also duplicate your selection using the command bar (search for "duplicate") or using the copy and paste buttons in the toolbar.