How can Particle Objects copy emitter's color texture? I'd like to make a scientifically accurate animated snake using particle objects (and no, sculpting or bump mapping won't be realistic enough because real scales don't actually shrink and stretch when the snake bends, they overlap or move away from each other, like particles do).
As per this answer Particle Object to Inherit Uniform Colour from Emitter I managed to get the scales to have ONE color sampled from the emitter thanks to the &quot;from instancer&quot; checkbox.

Cute but not good enough!
Real snake scales have multiple colors EACH, they're not actually pixilated!

So this is what I hoped to achieve, an imitation of real life:

This would not only make my snake 100% realistic, but also make my life easier as I would only have to paint a pattern onto the body mesh which then reflects perfectly onto the scales... but even though I tried to follow the instructions from the follow-up answer on the previously mentioned post, which supposedly would make the scales go &quot;chamelleon-like&quot; just as I need them to, I can't for the life of me get it to work!
each scale has the same rainbow as the entire body, rather than only copying a small area in their vicinity...
I've tried:

making sure everything shares the same origin.
making the original scale object have the same size as the whole body (scale applied)
making a completely new file with simpler objects (cubes and planes)

nothing works.

Here's the file, hopefully containing new updeated texture:  
Any help will be appreciated!
Use UV From Instancer to offset a large UV gradient. So a scale shows not just one point from the texture but a small area around.