Wayne McGregor’s 20 years as The Royal Ballet’s Resident Choreographer was celebrated in Alchemies, a triple bill of abstract work fusing his choreographic language with spectacular designs and diverse music. The world premiere of Quantum Souls was dominated by percussionist Beibei Wang, performing onstage among the dancers who responded with a pulsating vitality that matched her vibrancy. Unusually, for McGregor, structural improvisation had dancers reacting in the moment to the variety of percussive rhythms.