forge of empires plunder great buildings

What do 'easily' and 'enough' mean? Not enough to acquire a GB in any reasonable amount of time - one needs to spend FP on other players' GBs to have any hope of acquiring enough BP, and even then one gets mostly duplicates. So you can easily accumulate enough blueprints for a level per week, on average You'll get about a 1% drop rate for blueprints when you Aid/Motivate/Polish Gee, maybe because the whole point of the trading feature seems to be to get missing blueprint pieces, which is an obvious thing to want to do, especially if one doesn't know about the unlock feature and is months away from being able to use it. More to the point, WHY are you trying to convert them? What a strange thing to believe it certainly isn't true.

Try each of them, until you find the active one.

You can't see it visually, but only the most recent double or triple will work. Trading will almost never get you the piece you want, it will just deplete your spares. The blueprint pieces aren't equally likely some are very unlikely. Your doubles are no longer doubles, and now one of the other squares is a double, or possibly a triple. I have done that on several buildings and nothing at all happens.

Forge of empires plunder great buildings