Put Down the Carving Tools, This Marbled-Pumpkin DIY Is the New Jack-o'-Lantern

Pick your colors, and in separate cups, mix one part paint with three parts pouring medium. This will make the paint consistency much more liquid-y, which is exactly what you want, since you'll be pouring, as opposed to brushing, the paints. Then pour all the colors into one larger cup, but leave them unstirred.