Joy is...

... two young boys on a borrowed bicyle barrelling down the hill towards us, one across the bar and the other holding him tight, both bellowing with excitement at the sky, sunshine, passing trees, and at us as we jump onto the grass verge out of their way.

And it is also how we applauded them as they flew by, celebrating with the contagiousness of their abandoned joy. And how one of them looked back in astonishment at us when we did, still yelling, for several long seconds, leaving the bicyle and its cargo without a navigator.

And how even after they gave the bike a sharp turn at the bottom of the hill to tumble out harmlessly onto a soft grassy landing, both boys scrambled to their feet to look curiously back up the hill at us, two girls much too old to understand the secret exhilaration of that first dangerous flight.