I came across this old discussion on a bumped thread and realized there's a mechanic that I've used but never seen discussed. It actually is possible to use food tiles twice but it's clearly an exploit for the HOF. The trick comes from the processing order on the interturn. First commerce is collected in all towns. Then each town goes one by one (I'm not sure if the order is fixed or variable, but I do know my capital has been first or very high on the list throughout a game) first collects the new food, calculates whether or not it grew, assigns the new citizen to the "best" tile then collects the shields. So far so good, but the exploit comes when a build completes. You can then zoom to the town and rearrange the citizens. No problem. This is perfectly allowable under HOF and GOTM (I think) rules. But you can ALSO use the arrows to navigate to other towns that have not yet processed their builds and rearrange their citizens. This is very clearly illegal for competition, but not for the reason that you stumbled on here. The traditional use of this exploit is to use high commerce tiles to collect gold, then change them to high food/shield tiles. A player could also wait until after Town A had completed the build, and break into the build order before Town B processed to rearrange town A and B such that B gets to use the cows for a second time. In fact, this seems to me to be a far more powerful use early in the game - it might let two towns function as 4 turn settler factories despite unspectacular resources. But there is another situation in which I have used the same tiles production for two towns on the same turn, and it is entirely legal (though "exploit" is up for debate) as far as I can tell. Preconditions: Towns A and B that share a high production tile The towns process such that A processes before B B will grow next turn A completes a build next turn and has a worker on the high production tile The governor set to prioritize production only Then you can zoom to A after the build completes and move the citizen off the high production tile. When B grows the new citizen will go to the high production tile and reap the shields a second time that turn. This may seem like a hyper specific set of requirements, but it shows up quite frequently when town A happens to be a 1 turn worker pump. Sometimes Town B is also a worker pump and the dance comes every turn. Sometimes B is a two turn worker pump so you get the growth every second turn. Sometimes the benefit just comes occasionally. But if you had two towns that lacked a shield or two from both completing builds on the next turn it could be an effective strategy if the second town happens to be growing. It's also something to pay special attention to when you happen to have a strategic resource on a hill or mountain in your core, and might justify an adjustment to city placement.