Forgetting all theorising & just looking for patterns in observations, close contact in crowded spaces is the obvious front-runner for high transmission, but there seems more to it than that. What is it that connects through to, for eg, small gatherings for choir rehearsals?

Singing? Or, more generally, the vigorous *horizontal* expulsion of air from the lungs, as in coughs and sneezes, & as in speaking loudly or shouting over background noise. Could the bug be like Bobby Charlton (it's the change of pace over the first X yards that gives it wings).

The thought occurred when shopping in the local grocery store. All were carefully socially distanced, except one young staff member who was wandering around singing & shouting loudly to colleagues in other aisles, and I found myself instinctively 'avoiding him like the plague.'

There are interesting implications: might the Cheltenham races & Italian football match have been problematic not because of the crowds per se, but rather because of the roars of the crowds? Could the silence of commuters be helpful in returning to more normal working lives?

And what about speaking loudly to old folk loudly, so they can hear & understand you? And do bats squeak? So scientists, does the bug fall quickly to ground when expelled downwards from the nose, or when emitted with little horizontal momentum by the quietly spoken? Just asking.