superimposed layers of threads each formed of very fine fibers that are in clusters and or slightly twisted only those in the upper layer such as threads 6 and 7 are visible in fig1 as shown in fig1 a and 1b the warp thread 6 of the upper layer passes alternately above three consecutive pairs of adjacent weft threads such as 4 1 5 1 4 2 5 2 and 4 3 5 3 then under the next pair of weft threads alternate threads of this upper layer pass over and under the same pairs of adjacent weft threads as the thread 6 as shown in fig1 b the thread 7 passes alternately under the pair of adjacent weft threads 4 2 5 2 which is located in the middle of those over which the thread 6 passes then over the three following consecutive pairs of adjacent weft threads 4 3 5 3 4 4 and 5 4 and 4 5 5 5 as shown in fig1 a and 1b warp threads 30 and 31 of the lower layer each passes alternately over the pair of adjacent weft threads located in the middle of those over which there passes a warp thread of the upper layer then under the three following pairs of adjacent weft threads thus in fig1 a warp thread 30 passes over the pair of weft threads 4 2 5 2 and then under the pairs of weft threads 4 3 5 3 4 4 5 4 and 4 5 5 5 while in fig1 b warp thread 31 passes over the pair.