Today's footballs are more complex than past footballs. Most modern footballs consist of twelve regular pentagonal and twenty regular hexagonal panels positioned in a truncated icosahedron spherical geometry.  Some premium-grade 32-panel balls use non-regular polygons to give a closer approximation to sphericality.  The inside of the football is made up of a latex bladder which enables the football to be pressurised. The ball's panel pairs are stitched along the edge; this procedure can either be performed manually or with a machine.  The size of a football is roughly 22 cm ( inches) in diameter for a regulation size 5 ball. Rules state that a size 5 ball must be 68 to 70 cm in circumference. Averaging that to 69 cm and then dividing by π gives about 22 cm for a diameter.