21 cars on a 7×9 lot. 60 seconds on the clock.
21 cars left
You have 60 seconds, starting at your first tap. A bump costs 3 seconds.
Drive the cars out in this order: 1, 3, 2, 6, 8, 13, 4, 16, 17, 18, 21, 15, 20, 19, 9, 10, 5, 7, 11, 12, 14.