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What happens when the three Construction stacks run out?
The designer confirmed this procedure in 2018, 2019 and 2021; the first-printing rules were unclear.
Shuffle the cards and deal three new stacks, but leave the three most recently revealed cards out: you shuffle only the other 78. Their effects are still used with the numbers on the new stacks, and their house numbers are simply lost. The first player completing a City Plan may also choose to reshuffle all 81 cards earlier.