Graphical representation of the area of a polygon

The plotarea or areaplot command finds the (signed) area of a polygon.

plotarea takes P, a polygon.
plotarea(P) draws the filled polygon, with the signed area. (The area is positive if the polygon is counterclockwise, negative if it is clockwise.)

plotarea(polygon(1,(1+i)/2,1+i))

The fill color can be changed as a local feature (see 26.3.2) and the position of the legend can be changed (see Section 26.3.3).

plotarea(polygon(1,1+i,(1+i)/2),display=red+quadrant2)