lat-puzz.com

This one has been circulating on Facebook lately, so some of you might have seen it. But for those who haven't, here's a fun puzzle: What was the good reason for the rather unusual shape of this bridge?

Does it only work when the bridge is over water? When the bridge is made from stone? When the bridge has an arch? When it's for pedestrians? Is it for pedestrians? Is the purpose to make smooth turns? Does the bridge connect more than two points? Is its compactness in some dimension relevant? Avoidance of stairs?

Is the relevant part that the path continues under the bridge? Does it continue? or just end under the bridge?
Is there (or was there) a mooring place for boats under the bridge? are there boats travelling on the river?
Or was there a place to scoop water from the river in former times?
A toll or customs station?

Does it only work when the bridge is over water? Yes When the bridge is made from stone? No When the bridge has an arch? Not strictly speaking, but it must be open underneath When it's for pedestrians? No Is it for pedestrians? Possibly it is used by them, but this is irrelevant. Is the purpose to make smooth turns? In part Does the bridge connect more than two points? No Is its compactness in some dimension relevant? No Avoidance of stairs? This is necessary, but not sufficient

Is the relevant part that the path continues under the bridge? In large part yes Does it continue? Yes or just end under the bridge? No
Is there (or was there) a mooring place for boats under the bridge? No are there boats travelling on the river? but Yes
Or was there a place to scoop water from the river in former times? No
A toll or customs station? No

Is it made like this to make space for something? Or to make something fit?

Is something being loaded onto boats from this path?

Switching which side of the river you are on relevant?

Is the bridge relevantly used by: vehicles? Animals? Plants? Fungi? Pets? Livestock? Is getting on or off boats relevant? Loading or unloading boats?
Edit: is it for getting boats into the water? Out of the water? For carrying canoes across?

Is the bridge to be used by people who haul, tow, or otherwise handle the boat? Does the boat need to be hauled in this part of the river? because it's narrow? shallow? bendy?

Is it made like this to make space for something? Or to make something fit? Technically yes to both, but may mislead.

Is something being loaded onto boats from this path? Not relevantly

Switching which side of the river you are on relevant? Well, it's a bridge, so yes... for some definition of "you".

Is the bridge relevantly used by: vehicles? No Animals? Yes Plants? No Fungi? No Pets? No Livestock? Yes, but be careful of FA Is getting on or off boats relevant? Hmm... Yope Loading or unloading boats? No. While people may well have loaded items onto boats from the path, this is irrelevant.
Edit: is it for getting boats into the water? No Out of the water? No For carrying canoes across? No

Is the bridge to be used by people who haul No, tow Strictly as worded No, but will probably mislead. And the bridge would have worked well, in the same way, if the answer was a straight "Yes" , or otherwise handle the boat? Does the boat need to be hauled in this part of the river? No, the boats were NOT hauled, they remained in the water the entire time, and this is relevant.

Were these boats the kind of ferries that were towed by horse? And this was to let the horses switch sides?

Were these boats the kind of ferries that were towed by horse? And this was to let the horses switch sides? Yes! or sometimes by mules, apparently. Now why would a more typical bridge design create a problem when the horses needed to cross the river/canal?

So, an ordinary bridge would mean the horse would cross to the other side while the boat would pass under the bridge. Thus, the ropes binding the horse to the boat would have to be untied to allow the horse to move on. But this bridge allowed the horse to pass under the bridge as well, taking the ropes along with it?

So, an ordinary bridge would mean the horse would cross to the other side while the boat would pass under the bridge. Thus, the ropes binding the horse to the boat would have to be untied to allow the horse to move on. But this bridge allowed the horse to pass under the bridge as well, taking the ropes along with it? Exactly!

This bridge was built over a canal along which boats used to be towed using a rope by horses walking along a path at the edge of the canal. For whatever reason, the horse path needed to cross the water near this point. With a typical bridge design, the rope would need to be untied, and likely one of the passengers would need to disembark, carry the end of the rope around/over the bridge, and then get back in after the boat came out the other side, to avoid the tow rope getting snagged on the bridge as the boat passed under it. With this design, the boat needed merely to pause briefly in the center of the spiral to allow the horse to walk around the boat and over the bridge.

Not a very difficult puzzle, but I thought this was a laterally clever design when I saw it.

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That is indeed a very clever bridge! Good one!