A rectangular panel for floor-, wall- or ceiling coverings is provided comprising a visible decorative side, wherein the decorative side comprises at least one undulated edge line, which extends along the long side edges of the panel, said undulated edge line having a different design than the rest of the decorative side. In the provided panel(s), the physical edges and the optical edges may diverge, which provides the possibility that multiple panels can be installed as floor ceiling or wall covering in a way that the physical edges in a corresponding covering become almost invisible whereas the optical edges (i.e. the undulated edge lines) are perceived as artificial optical edge of virtual panels forming the covering.