Abstract: An apparatus is provided for use in optimally arranging covering units, such as tiles or the like, or for enabling the precutting of such covering units before such units are applied to the floor or wall or ceiling to be covered. A first prescaled grid is provided on a substantially opaque sheet of paper on which the dimensions of the surface to be covered may be laid out. The exact dimensions of the floor, wall or ceiling to be covered may be laid out to scale on the first substantially opaque sheet. A second grid or line arrangement corresponding to the dimensions of the covering unit is provided on a substantially transparent sheet. This second grid is scaled to correspond to the scaling of the first grid on the substantially opaque sheet.