What's wrong with this picture revealed

This one was perhaps a bit tricky if you're not familiar with how things normally work at Terminal 1, especially because I didn't show you how it started. That said, for anyone who looks at this everyday, one of these airplanes sticks out like a sore thumb. Let's take another look at the original photo:

Here, in addition to the Virgin America A319 on the concrete pad, we see a pair of Southwest B737s in play. Both have just pushed off their gates: The one on the right came off Gate 11, the one on the left came off Gate 13. For those playing along at home, here's a shot of the north end of Terminal 1 showing aircraft parked at those gates with the gates numbered for reference:


The following two shots illustrate normal pushbacks from Gate 13:

The first photo shows the usual push off Gate 13: Tail west on Delta, behind Gate 14. This sets the aircraft up for the concrete pad, and is the most common Gate 13 operation. We probably do this a dozen times a day. In the second photo, Shamu demonstrates the alternate way to push off Gate 13: Tail east into the top of the D-7 alley, behind Gate 11. This position allows the aircraft to either go onto the concrete pad or straight ahead on Delta, and, as seen here, can also allow an inbound aircraft to pull onto the gate while the outbound disconnects from the tug. We do this less often, maybe once or twice a day; it's generally only done when there's some benefit to the ground controller. So now, take another look at our special aircraft from the other day:


The question that immediately comes to mind is 'How did that airplane get there?' This Southwest B737 was parked at Gate 13, which is just beyond the right edge of this photo. As we've just seen, a normal pushback off this gate puts the aircraft on Taxiway Delta, either facing westward behind Gate 11 (not possible in this instance because the other Southwest B737 was pushing off that gate) or facing eastward behind Gate 14. In this case, they got it in the right place, but the tug crew somehow got the thing pointed northward on an east-west taxiway. I guess they were a little unclear on the concept; they did at least place the nose gear on the taxiway centerline. This operation would not have worked had there been an aircraft on Gate 14 at the time. As it was, I imagine the windows along the north side of the terminal shook considerably when the plane powered up for taxi.