Using two or three US passports to stay in the EU longer

Does any one know if this scenario is possible?

I thought I lost my passport 6 months ago, I ordered a replacement but a couple days ago I found my old passport. Great now I have two. In theory could I double my legal stay in Poland by entering and exiting after three months on one passport and then stay in Ukraine for a couple of days and then re-enter on my 2nd passport which is clear? Aside from being illegal, has any one every done anything like this?

you have 2 passports but each of them has the same number and it's in the system that way... you should get your ass to the embassy and extend your stay...

No you can't. It used to be that way a loooong time ago. But current regulations are very different.

Doesn't work like that - your data is scanned at the border and will be caught quite quickly. In fact, it doesn't matter - you'll get caught on the exit from Schengen because the stamps won't add up.

I can assure you that after a few trips to Ukraine over the last two weeks - every passport is scanned and details collected.