In figure ground, only 1 shade of gray is used to shade the entire scribble sections. Any area that shares any portion of its shape with the border does NOT get shaded in. Depending on the sccibbles, the emerging forms can have vastly different characteristics …fun to see them emerge. Here are some samples from the class on August 8, 2014.
Figure Ground with scribble NOT touching the border, vertical
Figure Ground with scribble NOT touching the border, horizontal
Figure Ground when scribble crossed the border – here you encounter the intuitive in “deciding” which is to be included in the figure that wants to emerge.
Image from Carmen in Spain