Nor Cal rock art

One of my best, I have a large collection of stone art from northern California tribes. They are representations of the art form described by the French apon first contact. They are illusion stones, the intended artistic image is hidden, the first step is the sideways lighting, or a raking light. The shadows created by the surface texture create a design that when viewed correctly exposes a hyper-realistic image. The images are hidden using an adaptation we developed visually for survival. Not sure of the formal name but I know it as, " how much of a bear in the woods do you need to see to know there is a bear in the woods.". There were posters in the eighties at head shops that were popular and used the same adaptation as a means of hiding the intended image until viewed correctly. Eg. One was a blue design, different shades of blue, abstract, no identifiable images until viewed briefly passively. Looking at the thing as a whole, not focusing on any particular details, relaxed, slowly looking for any shapes or patterns of the seemingly random design.
Looking for any areas of depth works best with the stones. Relaxed is key, your mind wants to identify anything it recognizes as fast as possible and move on, you have to accept that the image that will materialize will be foreign, not intuitive. TBC

When lighting is correct, low ambient with a raking light showing the shadowing created by surface texture. Everything being correct an image will materialize, a 3-d image, actually images, stones have multiple images on them and there will be images on all sides of the stone from any vantage point with correct conditions. Stones almost always have a distinct Main base or bottom and usually have 3 or more ways it can sit to be viewed. Like a painting that can be repeatedly flipped over showing a different image with each flip. When viewed in profile the shape of a head is almost always recognizeable, often very cartoony, big nosed, native leaning in appearance. Intentional, that and any rudimentary images you can find in full light are there to satisfy the uninitiated as to what it is, satisfied, viewer moves on, no closer inspection needed, intended images remain hidden for those in the know. Actual image is a lucid illusion, when you see the art work, hyper realistic, 3-d to the point images are protruding from the stone. The stone has visual information carved on it, not the image but enough of the image for your mind to fill in the blanks. Lazily looking at clouds produces the exact same illusions, there never was an airplane in that cloud, enough pieces arranged for your mind to create or finish what your seeing into that airplane, but the image of the plane is a combination of the available visual info and what your mind creates to identify what the image is given the visual info available. The hyper 3-d nature of the image is do to the fact that only part of what your seeing is coming from the stone visually the other part of the image is created in your.mind as it identfies what is there basesd on available info. They show enough of a bear for you to know there is a bear if you will.

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

Bone carvings, wood carvings, same artistic style[You must be registered and logged in to see this image.]

How much of a bear do you have to see? I like it I call these effects triggers, sometimes very subtle details, or a collection of them bring the whole bear to life, just like you're describing. I go into it here on this post of mine also https://eoliths.blogspot.com/2021/01/portable-rock-art-and-figure-stones.html and also ambiguous optical illusions, this is a favourite trick of prehistoric people. I find what you have said about the French documenting Indian stone carvings very interesting, have you got a link to the source materials?

Here is a pic from one of my finds that has a good example of How much of a bear do we need to see to know there is a bear?
The image I'm refering to is not the whole bear, over lapping Indians, or the beast like face, but the wild boar. Only the tip of its snout, an eye and a weak ear indication can be seen, but I can still see a hidden wild boar image, can you?
[You must be registered and logged in to see this image.]
From: https://eoliths.blogspot.com/2017/07/mind-blowing-portable-rock-art-video.html

Nice, this is a stump at the property I been exploring, can you see the Indian head at left, zoom in, the whole stump is worked.  The stones that are of the illusionary in nature have a surface etching, I call it the fabric, I'll post a couple pics.[You must be registered and logged in to see this image.]

The rock that got me collecting, notice the surface markings[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

Some stones[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

I'm not getting the stump and the others, but the last two above trigger me, I always go for the key glyphs, as this way it completely rules out paredollia, just like the configuration of letters in a book tell us we are reading English, the key smybols tell us we are looking at an ancient work of art.

On the black and white stone, above my thumb, see an Indian lady?  Not the artis[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
ts intended image, decoy to satisfy the uninitiated.

Not getting the stump? [You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

Thiis one shows an elephant head and when flipped shows the long necked water bird, just like in my chart this is a common combo, an ambiguous optical illusion. Great find, and thanks for the share.[You must be registered and logged in to see this image.]

Decoys, check this one, there is what can be seen as a buffalo head, flipped, a catfish coming out off the water.  Also on the bottom a mount[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
ain goat and an approaching mountain lion. Can you highlight elephant and long neck bird, escaping me, decoys for sure but like to be able to see what your seeing.  Scroll above, black and white stone, Indian lady above my thumb, decoy.

Stump? [You must be registered and logged in to see this image.]

Couple more[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

One of my own from here in the UK.
[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

Notice how both could also be interpreted as having a smaller/different waterbird inset.

Billwerner wrote:Couple more[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

[You must be registered and logged in to see this image.]

This is fantastic!

Impressive artifact you've got there! I see many recurring faces that I see in the art that I find all the way over here in Kansas. Amazing how recurring features on these pieces show up in other pieces halfway across the continent, and even more amazing...halfway around the world as well in some cases! Such an intriguing obsession this is turning out to be!