When a soft foil contains two areas separated by a line of stiffnes contrast, buckling occurs exactly along the boundary. The image shows the phenomenon on a rubber foil, on which a paper tag is stuck. When the rubber is stretched, the foil folds exactly along the line of stifness contrast. The fold is so to speak refracted around the stiff area by Euler buckling, since the threshold for buckling is lower in the softer area.