crescent shaped ledge 23c in the flow path through the hole 23 the ledge 23c generates substantial turbulence in the flowable plastics material immediately before and during formation of the filament 24 it will be appreciated by persons skilled in the art that the method of assembly of the spinneret plate 11 illustrated in fig5 could be used in the embodiments of fig3 and 4 it is believed that the turbulence generated in the flowable plastics material immediately prior to and whilst the said material is being brought to a condition where the filament is being formed generates substantial shear across the width of the filament as the filament is formed and when the axial tension of the drawing apparatus and subsequent processing apparatus is relieved the differential stresses across the width of the filament are at least partially relieved by the filament adopting a pronounced helical crimp however to increase the crimp effect the filaments 16 18 20 22 and 24 may be formed in respective holes 15 17 19 21 and 23 to have a non circular cross section and fig6 illustrates one cross section comprising a full circular cross section with one quarter of the circle removed and when the filament is being extruded from the holes 15 17 19 21 and 23 the points a and b of the extrusion hole 25 illustrated in fig6 may be disposed close to the points a and b as illustrated in fig1 further the non circular cross section filaments 25 may be subjected to a rapid differential cooling which will again increase the crimp formed in the filaments fig6 shows the cross sectional area of a typical filament extrusion or spinneret hole 25 it has been noted that.