In 1981, a study Kodak paid for and signed told the company that digital photography would kill film within a decade. Kodak read its own warning and used it to squeeze a few more years out of film instead. The company that invented the digital camera filed for bankruptcy in 2012.

It almost went the other way. Kodak got two clean chances to undo the same mistake, the first in 1981 and a second in 1996. Across the Pacific, a company caught in the identical trap made the move Kodak wouldn't, and it's still here today, inside most of the screens on Earth.

What if Kodak had believed its own people?

This week we hit Control Z twice on the warnings Kodak refused to read, follow both timelines forward, and find the lesson underneath: an early warning is only worth anything if you use it to leave.

In 216 BC, at a place in southern Italy called Cannae, Hannibal destroyed the largest army Rome had ever raised, tens of thousands killed in a single afternoon. With the capital nearly defenseless, he chose not to march on it. That restraint let a broken Rome survive, and the Republic that lived went on to build the Western world.

It almost went the other way. Hannibal's own cavalry commander, Maharbal, urged him to take the horsemen and ride through the night, swearing they'd dine in the enemy capital within five days. Hannibal said he needed time to think. The reply Maharbal threw back has echoed for twenty-two centuries: you know how to win a victory, but you don't know how to use one.

What if he'd listened, and turned the horses north at dawn?

This week we hit Control Z on the victory Hannibal couldn't use, follow the march to the gates of Rome, and the very different world it leaves behind.

In December 2000, the Supreme Court stopped Florida's recount and let George W. Bush's 537-vote lead stand. Those votes, out of nearly six million cast, decided Florida, and Florida decided the presidency.

It almost went the other way. Seven of the nine justices agreed the count was broken. They split on the fix. Five voted to stop. Four voted to send it back, set one standard, and finish. The man in the middle was Anthony Kennedy, who agreed the recount was broken and then voted to end it instead of fixing it.

What if he'd changed his mind on that one question, and said count it instead of stop it?

This week we hit Control Z on the vote that didn't switch, follow the recount to its finish, and the very different country it leaves behind.