▁the ▁form ▁p . q . p . q . p . q ▁or ▁( p . q ) 3 ▁with ▁a ▁symmetry ▁of ▁order ▁ 3 . ▁Here , ▁term ▁dit rig onal ▁refers ▁to ▁a ▁hex agon ▁having ▁a ▁symmetry ▁of ▁order ▁ 3 ▁( tri angular ▁symmetry ) ▁acting ▁with ▁ 2 ▁rot ational ▁or bits ▁on ▁the ▁ 6 ▁angles ▁of ▁the ▁vertex ▁figure ▁( the ▁word ▁dit rig onal ▁means ▁" h aving ▁two ▁sets ▁of ▁ 3 ▁angles "). ▁ ▁Other ▁uniform ▁dit rig onal ▁poly hed ra ▁The ▁small ▁dit rig onal ▁d ode c icos id ode c ah ed ron ▁and ▁the ▁great ▁dit rig onal ▁d ode c icos id ode c ah ed ron ▁are ▁also ▁uniform . ▁ ▁Their ▁du als ▁are ▁respectively ▁the ▁small ▁dit rig onal ▁d ode c ac ron ic ▁hex e cont ah ed ron ▁and ▁great ▁dit rig onal ▁d ode c ac ron ic ▁hex e cont ah ed ron . ▁ ▁See ▁also ▁Small ▁complex ▁ icos id ode c ah ed ron ▁Great ▁complex ▁ icos id ode c ah ed ron ▁ ▁References ▁ ▁Notes ▁ ▁Bibli ography ▁C ox eter , ▁H . S . M ., ▁M . S . ▁Long uet - H igg ins ▁and ▁J . C . P ▁Miller , ▁Un iform ▁Poly hed ra , ▁Phil . ▁Trans . ▁ 2 4 6 ▁A ▁( 1 9 5 4 ) ▁pp .   4