An attachment slot includes a layer of flexible material and a cut formed within the layer of flexible material. The cut includes a first cut end, a second cut end, a first segment, a second segment, and a third segment. The first segment extends from the first cut end to the third segment and has a first curvature defined by a first radius of curvature at a first intersection between the first segment and the third segment. The second segment extends from the second cut end to the third segment and has a second curvature defined by a second radius of curvature at a second intersection between the second segment and the third segment. The third segment has a third segment length that extends from the first intersection to the second intersection.