I do love the colours that lie underneath the paint layer on my palette. If you use acrylic paint just try peeling the paint layer off carefully. You might be surprised what you find underneath. Colours that clash or harmonise. This works with Acrylics. It won’t work with watercolours and I think that oil paints would still be wet underneath.
You could take a photo of the outcome and play with it as I have.
Is this art? I don’t know, it’s related to art. If I did a series of these by creating new patterns, or photographing every palette I guess I could say it was art. Maybe a type of painting or even fluid art? I’m not sure.