I haven't posted lately as I have been making a lot of Copper Prosperity Feathers and Copper Roses with Brass Leaves. which are similar to ones I have done before.
A friend sent me this link and I think it will be of interest to those who like visual stimuli.
It is a collection of 78 Optical Illusions & Visual Phenomena http://www.michaelbach.de/ot/index.html

One of the examples is the "Turning Lady"

with which I am familiar. http://www.michaelbach.de/ot/sze_silhouette/
However, many are new to me and are good examples of how one perceives images.