(a.) Triquetrous.

centrifugal cuneate cuneated cuneiform delta-shaped deltalike divaricate divaricating divergent diverging fan-shape fan-shaped fanlike fanned fanning flabelliform flared flaring open outspread outstretched oxygonal palmate palmated patulous splay splayed splaying spraddled spraddling sprangled sprangling sprawling sprawly spread spreading stretched-out three three-cornered three-dimensional three-footed three-in-one three-pronged three-sided triadic trial triangular triangulate triarch trichotomous tricorn tricornered tricuspid trident tridental trifid triflorate triflorous trifurcate trigonal trigonoid trigrammatic trihedral trilateral trimerous trinal trine triparted tripartite triple triplex tripodic triquetral triquetrous trisected triune unfolded wide-open widespread