also be crenelated if the side walls of the strip are parallel the strip will wind into a cylindrical shaped body if the strip has tapered side walls it will roll into a cylinder if the smaller end wall is disposed to the interior and into a hexagon shaped body if the larger end wall is disposed to the interior of the packing body 10 as shown in fig2 the strip shown in fig1 and 2 has a very open structure like a mesh or a screen in the embodiment shown in fig3 and 4 the strip 40 is formed of sheet material the baffle elements 42 and the apertures 44 can be formed by stamping and bending appropriate materials such as metal certain plastics and certain precursor ceramics or they can be formed by molding in simple molding cavities or by casting the apertures 44 are preferably formed by sheet material raised from the surface along connection line 46 to form the baffle element 42 in the case of bendable materials the baffle element 42 is bent along line 46 to form the aperture 44 in fig3 the baffle elements 42 are shown with cut lines 48 along 3 sides joining bend line 46 which is parallel to the longitudinal axis of the strip 40 in fig4 the baffle elements 42 are shown bent away from the surface 50 of the strip 40 the tapered strip 40 is rolled with the wider first end 52 end forming a first convolution 54 at the interior of the packing body 56 and the second narrower end 58 forms an outer convolution 60 at the outer periphery of the packing body 56 the.