  Jordan showed that the incidence variety of a smooth cubic surface containing
27 lines has solvable Galois group over the incidence variety of a smooth cubic
surface containing 3 skew lines. As noted by Harris, it follows that for any
smooth cubic surface, there exist formulas for all 27 lines in terms of any 3
skew lines. In response to a question of Farb, we compute these formulas
explicitly. We also discuss how these formulas relate to Schl\"afli's count of
lines on real smooth cubic surfaces.
