Thanks to Ardwulf for his lunchtime "Immersive Worship". The theme was meant to be, as it often is, the mutual indwelling of the persons of the Trinity. This normally involves Liturgical Dance. And who doesn't like Liturgical Dance?
Cue 30 minutes of watching, puzzled, as Ardwulf sprinkled rain water over a dusty floor, while an industrial fan wafted the scent towards us.
Eventually the penny dropped, and I pulled the plug - on the fan, and the liturgy. Easy mistake, I realise, caused by somebody's dodgy handwriting. That did look rather like "petrichoresis".