For their iridescence and the easy way they round edges, Trisha Brown’s dances might all be called Opal Loop. But the actual Opal Loop, from 1980, appears on the company’s program at the Joyce with its Irish twin, the 1981 Son of Gone Fishin’, whose form the choreographer likened to ripples that emanate from a stone dropped into water. Brown, who died in 2017, is a dancer’s choreographer not because dancers worship her but for the reason they do: in the dances’ radiant evanescence, they are Brown’s idea of a dancer’s body, writ large. For us civilians, the work is a lightly marked map of that cultivated terrain. A premiere by Australian Lee Serle, whom the choreographer mentored in her final productive years, complements the two iconic works. —Apollinaire Scherr