I once read about an interesting psychological experiment. Maybe you know it, if not read the following story:

A very powerful but crazy witch decides to cast a spell on all of humanity. With a wave of her wand, she will make all man-made objects disappear and return the Earth to 200,000 BC. What remains are 8 billion naked people standing on grassy plains, in forests, swamps, tundra and deserts in the exact places where their towns and villages stood just a second ago. The people themselves have not changed, and everyone has in their heads what they had in their heads - their knowledge, memories, etc.

In addition, each of them is now just holding a note with a message in their own language:

I cursed all mankind - because, why not? The rules are this: I'll leave everything as it is until humanity can create a fully featured and fully functional equivalent of the ThinkPad X61. Once that happens, the spell will wear off and all the original man-made items will reappear.

A minute later, all the tickets disappear.

Your task is to guess whether and possibly how long it will take humanity to produce a ThinkPad and reverse the spell.