Rotation changes the interpretation
from Michael’s Visual Phenomena & Optical Illusions
Some things change completely when turned upside down. Place your mouse over the neighbouring image, it begins to rotate. You may observe: the beaver (or water rat?) changes to a donkey.
Julian Jusim, Mirjam Pressler (1999) Kopfunter Kopfüber. Ein Bilderbuch zum Drehen. Carl Hanser-Verlag. ISBN-13: 978-3446196292
In the “fairy tale” at the left, bistable situations can occur at oblique angles. You can test this by stopping at the right instant.
I constructed this movie from the picture “a-j-a.gif” which I found “somewhere on the Internet”. It is also known as “(after) 6 beers”. Could anyone enlighten me about the original source? [It’s not from the “Invisible Monsters” cover, I had this image before that book came out.]
The painter Rex Whistler created a similar design “Cinderella and her fairy godmother”.
The top picture has been embodied in this neat coin design, the “Illinois Quarter”, on the right. It could (seemingly no longer) be obtained at Joel’s Coins (for a little more than a quarter ;-)).