The cat-and-mouse game of defensive scheming decided both playoff matches yesterday, but in different ways. In Denver, the Steelers stacked the box, daring Tim Tebow to throw. He did. But at the Meadowlands, on a pair of fourth down conversions, the Falcons telegraphed a pair of sneaks up the middle, daring the Giants to stack the box. When they did, Matt Ryan took it up the gut anyway. Mike Smith is a foolish mouse who tells the cat he's going to zig, then does.