If I read this correctly, basically if someone acquires 15% of the stock, then all of the other shareholders have to option to buy more stock at half-price. Is that correct? Where do these shares come from--are they just considered newly minted shares?

If so, couldn't something like this backfire or otherwise be circumvented? You're Musk and you want Twitter so you've started by buying 10% of the stock. Can't you just setup several shell companies, each of them also buying significant stakes each (say, 10% each). You're still going to eventually get enough to gain control... Heck, you could even then trigger the right outlined here by having Musk go over 15% and exercise your 100% of your rights in shell companies, potentially diluting other shareholder's overall stake in the company since not 100% of them will exercise the right (although I suppose that would be a bad/expensive idea if these share newly-minted shares). (???)