No passersby knew why he sat, in the sun, staring at nothing. A few threw coins or insults. One threw lunch, which he ate, staring as he chewed.
Night fell to all but the wall before him; the whiteness of antique, virgin brick burned into his mind. He paused to start a silent soundtrack. Nodding along to *bom!-bom!-bom!* he opened equally invisible paints.
Pain sprayed black in a wild arc, then red for beating love, then blue for days without the red; then green, grey, purple, orange –
Till, breathless, he stood staring at his soul upon the wall; satisfied.
For me, with the prompt provided by Carrot Ranch Literary Community.