deck system 72 and allows for longer spans as well as greater functionality recesses 60 may be open and concave upward as illustrated in fig2 a and 3 or closed and concave downward as illustrated in fig2 b if concave upward the top of the dove tail recesses may be used as added support for metal deck struts 90 as disclosed in application ser no 11 347 484 filed feb 3 2006 for a metal deck strut system as seen in fig4 which is identical to fig1 except for the addition of struts 90 the superior strength of the present invention over an otherwise similar bottom panel with dove tail recesses alone is illustrated by the following example assuming a uniform load of 30 pounds per square foot and using 20 gauge steel the span limit of a dovetailed panel is 12 5 feet with a 20 gauge steel top hat profile attached to the dove tailed panel the span limit for the same loading increases to 20 5 to 26 5 feet depending on the height of the hat profile in addition to its great strength the present invention also adds to the functional aesthetics of a ceiling of a building covering a large area such as an airport terminal or an arena the concave upward dovetail recesses establish narrow gaps in the otherwise smooth panel liners to create a plank look from below this plank look gives the viewer a better indication of the perspective of the area as well as.