Imagine seeing your partner raise an arm in the back glass. You turn, but the movement is over. It looked impatient. Your reply is sharper than you intended.
Now there is something real for the partner to answer: the sharpness. A glimpse has become an exchange, and the exchange may begin to resemble what you first thought you saw.
In accounts of the Glass Court, every surface returns something altered. A ball, a gesture, a memory, an accusation: none comes back untouched by what it meets. The Glass School finds honest reflection here. Other Schools ask how readily resemblance begins to pass for truth.
Justice and the Moon stand beside the Glass Return. The glass has shown a relation between movements. It has not supplied the intention behind the first one. In the imagined exchange, asking about the raised arm might reveal a call for the next ball, a complaint or something else entirely.
The answer will not unsay the sharp reply. It may change what follows it. That is where the widely told Court becomes more than a picture: both players have a part in what comes back next.