The American Repertory Theatre presents Amerika or The Disappearance by Gideon Lester after the novel by Franz Kafka. When Karl Rossmann steps off the boat in New York Harbor, he is thrust into a whirlwind of adventures. The world he discovers in “Amerika” is beautiful and grotesque – he finds work in a hotel with forty-seven elevators, shares a room with a magnificently rotund opera singer named Brunelda, and seeks out the fantastical Nature Theatre of “Oklahama,” where hundreds of actors dressed as angels play trumpets from atop golden pedestals.