Three decades of dancing on air with Mark Morris

Janine Parker for The Boston Globe

We blinked, and suddenly the Mark Morris Dance Group is celebrating its 30th anniversary. Another blink, and it’s the last week of this year’s Jacob’s Pillow Dance Festival, during which Morris’s jolly troupe is performing four of the master choreographer’s works. The giddy program, too, flashes by: Time really does seem to fly when you’re having fun.