The present invention refers to a rectangular panel for floor-, wall- or ceiling coverings comprising a visible decorative side, wherein the decorative side comprises at least one undulated edge linewhich extends along the long side edges of the panel, said undulated edge line being designed different than the rest of the decorative side. In the panels according to the present invention the physical edges and the optical edges diverge which enables for the possibility that a plurality of panels can be installed as floor ceiling or wall covering in a way that the physical edges in an accordingcovering 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.