This was rather a nice swing bridge.  One of the things about swing bridges is (you guessed it) they swing.  In fact they swing quite well if you find one of the nodal points of its natural vibration frequency and rock it.  The Millenium bridge in London was one of these – badly designed. It swayed so much when people walked across they had to put damping on it.  People were getting sick and some fell over.  The Tacoma Narrows bridge is the famous one which shook itself to pieces in a high wind.

This is the same type of bridge, so naturally we found a nodal point and rocked it back and forth as much as we could, achieving a very satisfactory amount of twist and undulation in the walkway.  Unfortunately the builders had anticipated this sort of frivolity and put stabilising wires on the structure so we weren’t able to actually break it up.