24 may be of any suitable type they are illustrated as conventional t bar supports having a vertical leg 26 and a horizontal cross bar 28 the supports 24 are connected together at their horizontal intersections in a conventional manner to provide a lightweight surprisingly sturdy grid for receiving horizontal panels 30 thereby providing the horizontal ceiling area 16 the elevated horizontal area 20 and the transition area 22 provide a support structure 31 made of a plurality of horizontal intersecting supports 32 substantially identical to the supports 24 in the sense of being conventional t bar supports the structure 31 is illustrated to provide three types of inclined supports 33 34 35 the supports 33 extend perpendicularly to the horizontal supports 24 32 and terminate at the support 24 the supports 34 extend along the corners of the recess 18 which is may be thought of as a truncated pyramid having a square or rectangular bottom and which provide a support for an inclined flat panel the supports 35 extend perpendicularly to the supports 24 32 and comprise an upwardly angled extension of supports 37 the supports 33 connect to a mid point of the supports 24 32 by the use of connectors or clips 36 as shown in fig2 the.