Originally Posted by
Packetdancer
You can functionally trade materials for XP at an unbounded rate; you can reconstruct a landmark into another landmark instantly, but evidently it still gives you nearly the amount of XP that constructing a landmark for the first time does. So if you gather a sufficiently large amount of a very limited set of materials, you could hypothetically go to one landmark plot and reconstruct, say, the windmill into a treehouse into a windmill into a treehouse into a windmill into a treehouse into a...
I'm not sure if this is an oversight, or just not considered a balance issue. (Either way, it's an interesting design choice, though I can see the benefit; if you build the wrong landmark, you don't have to wait another eight hours or whatever to get the one you wanted.)