Suddenly, there was a freak break in the action, and I hit the transmit button. Miraculously, ground seemed to know who we were and where we were going, which was to Runway 4L. I was gratified that at least he knew what was happening, because despite what we thought was careful study of the taxiway diagram at O'Hare, neither of us could actually picture where we were in relation to the designated runway. That's because it was miles away, tucked behind the sprawling, curving terminal building around which we would have to go ducking and weaving around every kind of commercial jetliner. What do you do in that situation, with everything from regional jets to 747s in your face, pivoting right and left for their gates spewing jet exhaust, calls jamming the frequencies and a couple of hopeless novices craning their necks in every direction trying to find the right taxiway? You ask for the coup de grace: progressive taxi!