The experience of an NVA show isn't one that begins at the point marked "start" or ends at "finish", but includes other moments outside, like, for instance, making a fire on the beach at The Storr.

Angus Farquhar has led his audience to these wild places and with Speed of Light, an ambitious choreographed night-time work staged on Arthur's Seat, there is an even greater sense that the show is not just the show.

If you are participating as a runner and have spent months being sent training programmes, failed to do them, yet still find yourself there on opening night, the show has sent you on a bigger journey. Officially we 150 runners, dressed in our state-of-the-art light suits, are the performers, and the walkers are the audience. But it is more ambiguous, since both groups have paid. We are two different communities, two separate species, watching each other.

We buzz up to Salisbury Crags as the walkers, like pilgrims, make their own singular path up to the summit. We dart like fireflies in the night, stopping now and again to spin on the spot or send a winking message to the walkers with a torch.

As with almost all of NVA's big shows, what dwarfs all performance is the place. To see Arthur's Seat in this way, on foot and at night, against a dark sienna sky, with a half slice of moon hanging, is the real "ooh and ahh" of it all. Yet, at the same time this is also a tale of endurance, of the fight to maintain our spacing of 10 metres apart, not to lose our group. I do both: several of us "pink group" lose the rest, and end up bleating "pink, pink" like lost lambs. It's a buzz – and as much about how we work together as a species as why we run.

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