Alexei Ratmansky’s comic ballet Bright Stream has travesti roles for young men (the Ballet Dancer) and senior women (the “Anxious-to-be-younger-than-she-is Dacha Dweller”). Martine van Hamel, now 65, tried on a pair of pointe shoes and “the bones in my feet said, ‘Ah! Don’t do that!” And poor Cory Stearns couldn’t even tell which of his shoes was left and which was right.