A strange little side quest
If Mage Keshift sends you down a curiosity rabbit hole, start here. The word 'checkmate' is linked to the Persian expression 'shah mat', used when the king was trapped. A second detail makes the picture even better: In 1958, Tennis for Two used an analog computer and an oscilloscope to turn simple physics into a playable tennis-like demonstration. That gives Mage Keshift a little more company than it first appears to have.