It is a windy day. Across the street is a seven-storey office block with a flat roof. Two pigeons fly across the rooftop and over the edge. The gusting wind catches the pair, throwing them around in the air, tumbling them down towards the ground.
Nearing the ground, they fly out of the wind. Then around the building and back up on to the roof. They again fly across the roof, and out into the wind, and once again tumble towards the ground.
Then they fly around again. And tumble down again.
And on, and on, time after time, all afternoon.
Who said birds don’t play?