So Gertrude was going to meet Jack Bailey that night by the bridge!
"The Circular Staircase" by Mary Roberts Rinehart
These were Bailey, Tupper Falls, and Higgins's Bridge.
"Scattergood Baines" by Clarence Budington Kelland
The besieged had abandoned it since midnight, and had thrown down the bridge giving entrance to the bailey.
"Annals of a Fortress" by E. Viollet-le-Duc
See Figure 2 where this is illustrated for the Rolfsen-Bailey knot, i.e. the one obtained by attaching the exterior of the two bridge link 4 1 to the exterior of the left hand trefoil, as described above.
On two-generator satellite knots