Okay, so you must go now and read
Transhuman, by
gabby_silang. It may have been a long time coming but it is so totally worth the wait.
Extremis taken to the logical conclusion, pushed beyond the underused kernel of an idea from the comics into a terrifying kind of inevitability, because Tony Stark is who he is.
After the process, he hears voices he doesn't know how to hear. He has none of the mental groundwork laid to understand that he's being spoken to. The information passes through and around him and he can't sort it. Its organization isn't linear. It's two days later when in his mind's eye the page he's trying to read becomes cubic, and he follows it. He moves with it. He hears it.
It's a repeated transmission from a SHIELD orbiting satellite. It's been on a loop for days. It says, in mathematics, in spatial information, "Tony, can you hear us? Wake up."
So, yeah. You should go read it right now. This is what fanfiction is for. This is what it can do.