For the score of Inception, Hans Zimmer used mathematics to mirror its complex plot.

Christopher Nolan’s dreamworld sci-fi thriller Inception may have a fiendishly complex plot but composer Hans Zimmer says his initial idea was to keep the score relatively simple.

”I decided really early on to find an emotional line through the whole thing,” says Zimmer, “because I thought this was going to be a bit of an adventure for an audience. Then I got ambitious.”

That ambition led Zimmer, an Oscar winner for his 1994 score for The Lion King and a previous collaborator with Nolan on Batman Begins and The Dark Knight, to start exploring ways in which his score could mirror the film’s structure, which weaves together multiple parallel plot strands.

Zimmer pulled off the trick by taking the Edith Piaf recording which features in the film’s plot and creating “crazy sub-divisions of the rhythm. The original sub-division comes from the tempo of the Piaf track and everything beyond that is manipulating the mathematics of it.”

The Piaf song also led indirectly to the score’s brass section motif. Zimmer found the sound by imagining the song’s trombone part amplified “as if it were giant foghorns echoing off a city”.

Another notable element came about when Zimmer suddenly realised a sound he had been hearing in his head was the guitar playing of Johnny Marr, driving force of 1980s greats The Smiths. Marr was recruited to play on the score because, says Zimmer, “he can play a very simple phrase or very few notes with great commitment and conviction”.