• My old art teacher's classroom was done with the same effect as that Rossin (as was a Diamond Back Ascent I nearly bought once, in case anyone cares...). they had a machine with paint in a hopper and cranked a handle, and it spat out paint rivulets to give that effect on the wall. Probably not that difficult to do, but would require the machine to do it...

    I imagine there's a name for the technique...

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