structure however anywhere from two to twelve weft yarns may be utilized within these single fabric layer areas seams 16 22 the intermediate double fabric layer areas 18 20 comprise each only four weft yarns 28 within plain weave patterns the number of such intermediate weft yarns 28 between the single fabric layer areas 16 22 must be in multiples of two to provide the maximum pressure bearing benefits within the two seams 16 22 and thus the lowest possibility of yarn shifting during inflation at the interfaces of the seams 16 22 with the double fabric layer areas 12 14 24 26 fig2 shows the weave diagram 30 for an inventive fabric which comprises two irregularly shapes concentric circles as the seams such a diagram also provides a general explanation as to the necessary selection criteria of placement of basket weave patterns within the fabric itself three different types of patterns are noted on the diagram by different shades the first 32 indicates the repeated plain weave pattern throughout the double fabric layers 12 14 18 20 24 26 of fig1 for example which must always initiate at a location in the warp direction of 4x 1 with x representing the number of pick arrangement within the diagram and at a location in the fill direction of 4x 1 thus the pick arrangement including the specific two layer plain weave signifying block 32 begins at the block four spaces below it in both directions the.