If you are going to specify the fill color of polygons or loops, you will be able to select the fill attribute (regular) Fill or EOfill. Polygons and loops can be distinguished from other line-art shapes in the sence that that they are compound paths with intersecting lines. To determine whether a point is part of the shape or not, different rules can be applied: the standard rule or the even-odd (EO) rule. These rules determine the filling method of the shape.
The even-odd rule supposes that you draw a line between a point inside the shape outline (x) and a point (y) outside its outline. If that line crosses the line of the shape an odd number of times, the shape area to which the point (x) belongs, is filled. If the number of crossings is even, the area is not filled.