The classic definition of silhouette is '...Dark outline of something or someone against a light background...'
Pushing this a bit, what about a light outline on a darker background such as seeing a horse in a white cloud in a blue sky.
Or any contrasting colors, seeing the outline of the state of Florida in a potato chip held up to any wall.
An abstract outline shape on a contrasting background can be a silhouette depending on what YOU see.
The basis of the Rorschach test of using inkblots to have subjects describe what they see is based on this.
So... the idea of Silhouettes from Traditional to Abstract.
Sample of some of the Silhouettes, as more are completed they will be added. Click once on an image to enlarge.