Something was niggling at the back of Astragal's mind about that wobbly bridge. Surely there must have been something the designers could have looked up, as they grappled with the possibility of movement on what is an incredibly sophisticated (and therefore highly sensitive) structure. And here it is: a paper in Earthquake Engineering & Structural Dynamics , from issue 22 in 1993. Fujino Yozo and colleagues produced just the thing - a paper entitled 'Synchronisation of human walking observed during lateral vibration of a congested pedestrian bridge'. Read on . . .