This image is dubbed "Sky and Water which is one of the most iconic Gestalt images ever created. It falls into several areas including similarity, proximity and continuity. The multiple and closely related images creates complex illusion at first glance.
This reminds me of the piece Dr. Kristin Atchison went over with the 5 B's with ink spilled over. When the negative spaces changes from white to black, the image completely changes, and what was once seen, now is a challenge to comprehend.