This math fractions ClipArt gallery offers 5 illustrations of a four sided polygon broken into fourth slices. This includes images of individual slices, as well as the polygon with missing slices.
1/4 of a 4 sided polygon
2/4 of a 4 sided polygon
3/4 of a 4 sided polygon
4/4 of a 4 sided polygon
4/4 of a 4 sided polygon with one piece detached