The Act One set begins as a vast ship's hull panorama, but a panel slides open to reveal Isolde's glass cage compartment, and another slides open on the right to reveal a neatly negotiable ship's ladder, and another on the left to reveal an empty space. There's a huge black prompter's box center stage. A yellow, glowing half-circle frame descends, making a pretty picture of the pair, with descending fake stars in the background. Brangaene sings from her lookout on top of the cage. Wonderful lighting effects abound.
Real flames shoot up around the two during the climax of the love music.
The forest pops back up when Marke arrives on the scene, and a blood-smeared transparent panel descends when Tristan is wounded by Melot. Three plops the glass cage in the middle of the lumpy hills of Kareol. Here the stage directions are more innovative than the scenery. Kurwenal commits suicide, and, during the opera's final chords, Tristan comes back to life briefly to embrace Isolde. I have three color slides that I will put up at this site when I get a chance to convert them.