Watching the players of the London Sinfonietta and singers of Synergy Vocals last Tuesday evening was akin to watching a small army of ants create a towering anthill. Set up as Steve Reich stipulates in his performance notes for Music for 18 Musicians, the multi-talented artists moved around the stage, swapping from piano to marimba, xylophone to maracas, relieving fellow performers of repetitive strain injury.

And it was a tower of work. 55 minutes of throbbing, pulsating repetitions that seem to take you out of time and mess with your memory.

Music for 18 Musicians is based on the rotation of eleven different chords stated at the very beginning and again at end of the work, each one lasting the duration of two breaths, as stipulated by the gesture of bass clarinettist Timothy Lines. These chords are then used as the basis for smaller pieces within the structure of the work. It’s at once incredibly simplistic yet decadent, and it envelopes you in it’s multiplicity of churning patterns and deposits you gently the other side of an hour in a daze.

Against relentless rhythmic activity from the percussive instruments (four pianos, three marimbas, two xylophones), the clarinets, strings, and voices provided what Reich has likened to waves lapping against a shore. The four singers pitched immaculately, and by moving microphones slowly towards and away from their mouths with incredible control, created achingly incremental changes in dynamics.

Besides the mesmerising sonic effects were wonderful spectacles: pianos playing host to four hands, one marimba struck by three players simultaneously in a tangle of limbs, four bright yellow maracas beating in perfect unison.

The result is a complex, seemingly unstoppable, mechanical-sounding structure, but one that is entirely dependent on the physical nature and capabilities of its human performers.

This bionic balance is captured in crystalline form in Clapping Music, which opened the concert; a study in miniature of many of the principles of minimalism. Two musicians, using just their bodies, slowly shifting a pattern to hypnotic audio effect.

The brunt of the first half was given over to the first UK concert performance of Runner, written in 2016 for Wayne MacGregor and the Royal Ballet. It bore all the classic signs of Reich — a Ghanaian bell pattern divided and manipulated — but against the towering 18, it felt a little redundant (as did its conductor Andrew Gourlay). The audience reaction at the very end of 18 — a warm, a standing ovation of thousands of clapping hands — seemed to confirm this.