Entanglement

Entanglement is a joint state of two or more qubits that cannot be written as each qubit having its own amplitudes on their own. Measure one and you learn about the other, even at a distance, but answers written in advance could do that much. What marks entanglement is that the tie holds across several measurement directions in a way no answers written in advance can match.

You do not get to choose which outcome appears, so the link is no route for a message you composed in advance. Keith still asks, about once a month, whether a clever setting could smuggle a word through, and the tally of those questions is on the cork board beside the kettle.