characteristics and method of making same u201d and incorporated hereinto by reference another exemplary honeycomb core and facing sheet assembly is described in u s pat no 5 701 621 issued on dec 30 1997 to landi et al entitled u201c liner for overlaying a mattress u201d and incorporated hereinto by reference the cell walls and or the one or more facing sheets can be perforated for improved air circulation for example the perforated cell walls and or facing sheets can be formed as described in u s pat no 5 180 619 issued jan 19 1993 to landi et al entitled u201c perforated honeycomb u201d and incorporated hereinto by reference two adjacent sections of a honeycomb core or a honeycomb core facing sheet assembly are joined together with a seam where the seam is formed on an underside of the mattress or mattress overlay i e away from an upper or sleeping surface on the upper or sleeping surface the seam may or may not create a slight depression a mattress overlay is typically thinner than a mattress and is configured to lie on top of a mattress e g a conventional spring mattress and may be secured with straps self adhering fastening strips or pads or the like the mattress overlay provides additional comfort and support to the user referring now to fig1 of the drawing an embodiment of a mattress or overlay section formed of a prior art honeycomb core 102 and a pair of facing sheets 104 105 is shown generally at 100 the technique for forming the honeycomb e g as described in the above referenced landi et al patents.