De-projected maps of the gravitational torque and the CO(3−2) emission. Top: map of the gravitational torque, t(x, y)×Σ(x, y), in the center of NGC 1808. The torques change sign as expected in a four-quadrant pattern (or butterfly diagram). The orientation of the quadrants follows the nuclear bar’s orientation. In this de-projected picture, the major axis of the galaxy is oriented parallel to the horizontal axis. Bottom: de-projected image of the CO(3−2) emission, at the same scale and with the same orientation, for comparison. The ILR is indicated as a red circle.