Complex sentence: The themes of "My Arm" were developed in Crouch's second play, which takes its name from Michael Craig-Martin's An Oak Tree in which the artist asks us to think that he has changed a glass of water into a tree.
Split into simpler sentences: The themes of "My Arm" were developed in Crouch's second play, "An Oak Tree". This takes its name from Michael Craig-Martin's An Oak Tree in which the artist asks us to think that he has changed a glass of water into a tree.