Black walnuts need to ripen a few weeks before they’re ready to hull and shell. Then the hard part starts. It takes brute strength and tenacity to bust open the outer hulls. Some people crush them between stones, stomp them with big boots and brogans, or go at them with mallets and drills. Others strew the nuts on driveways or other hard surfaces, and then drive slowly over them, although that process tends to scatter the results. The walnuts leave messy evidence of this struggle. The pigment that once made them excellent dye for homespun cloth leaves dark, chocolate-colored stains on skin, and sinister smears on carports and porch steps. Like a chalk outline at a crime scene, we might not know what happened, but it’s clear where it happened.