// quad( color )
// returns quad (tetrad) variations of given color

ks-quad( color )
    first = spin( color, 90 )
    second = spin( color, -90 )
    third = spin( color, 180 )
    ( first second third )

quad = ks-quad unless ks-no-conflict
ks-tetrad = ks-quad
tetrad = ks-quad unless ks-no-conflict