choose polygon tool
set the style of the templateGraphic to polygon
When using the Polygon tool, the cursor is a crosshairs shape (over stack windows) or an arrow (anywhere else). This tool is used to draw an irregular polygon in the penColor, filled with the brushColor (or brushPattern).
If you try to paint with the Polygon tool on a card that has no images, an image the size of the card is created to hold the painting. If the current card already has one or more images, painting outside the image has no effect.
Setting the style of a graphic(keyword) to "polygon" makes the graphic(keyword) into an irregular polygon(keyword). Irregular polygon(keyword) graphics, unlike painted polygons, can be changed and reshaped: use the points properties to change the shape.