6. Bridges
The green bridge into town spins from its centre. The white bridge further down pulls up either side. Some bridges open only one part, while some are massive and use impossible looking counter-weights.
When a boat sails down the Sparne a dedicated employee cycles out to open each bridge in sequence. It’s like watching a puzzle game. Swing this one. Slide that one.
Once the bridge closes they’re off on their bikes to open the next one.