These pencil sketches are solutions to a design problem in the book Design: Principles and Problems by Zelanski and Fisher. The problem is to create a figure-ground reversal using black and white. In a figure-ground reversal, the figure and background are ambiguous. Is the black the figure or background? How about the white? The simplest examples of this are a checkerboard and the yin and yang symbol. M. C. Escher was a master of this design technique. For example, Sky and Water I is a well-known Escher piece that uses this technique.
Karl Zipser has a post titled Why does art change with viewing? that gives additional examples of figure-ground reversals. He shows a famous illustration that can be seen in two ways: as a pair of faces looking at each other, or as a vase. He also shows a drawing that can be viewed as a rabbit or a duck.
I found this problem to be very difficult. I see potential is the first two sketches (fairies emerging from between bottles and the snake plant), so I will develop them further.