The pendulum-harp's design changed a great deal over time. Bjork recalled to Stereogum
: "I gave him the song I'd already written and then he said 'to play that you need more than one pendulum, you actually need 38 pendulums.' And I was like 'WHAT?!' and I was like, 'Oh that's a shame and then he's like because its 38 arms it needs to be like 30 feet tall otherwise they'll hit each other.' And I was like, 'Damn ok, oh because they're 38 and they're 30 feet tall they need to be made out of aluminum.' And I was like 'WHAT?' and 'because it's aluminum it has to be motorized' and I was just like 'Ok…this is not going the right way.' And then he'd worked on it for a whole year so it was really really difficult. I just had to stop it I said, 'Listen it has become the opposite of what its original intention was that it was effortless.' It was Spinal Tap reverse. We [now have] four pendulums that are each a few notes. You can hang them either in the ceiling or on a branch or something. They're about two meters tall and made of wood."