For the Manchester International Festival 2007, Eliasson installed mirrored curtains across the stage of Manchester's Opera House, reflecting the audience's gaze back on themselves. The orchestra and conductor faced the audience and, in the dimly red-lit hall, began to mimick the audience's sounds. At first, flutes imitated coughs and clarinets reproduced subtle laughter, but soon the entire orchestra joined in, as the call-and-response game invited shouts, ringtones and applause from the audience. This shift from pianissimo to fortissimo accompanied the growing intensity of the sodium lights, which gradually shifted from soft red to bright yellow over the course of the performance.