setup with a calculating look. Tellman's display was a flat, showing a hypothetical solar system as seen from above the plane of rotation. The three planets were small disks of light moving around the primary. Their size gave a clue to mass, but the precise values appeared near the bottom of the display. Departure and arrival planets moved in visibly eccentric orbits, the departure planet at one rev every five seconds - fast enough so precession was clearly occurring. Between it and the destination planet moved a third world, also in an eccentric orbit. Rosas grimaced. No doubt the only reason Tellman left the problem coplanar was that he didn't have a holo display for his Celest. Mike had never seen anyone without a symbiotic processor play the departure/destination version of Celest at level nine. The timer on the display showed that the player - the kid - had ten seconds to launch his rocket and try to make it to the destination. From the fuel display, Rosas was certain that there was not enough energy available to make the flight in a direct orbit. A cushion shot on top of every-thing else!

The kid laid all his bank notes on the table and squinted at the screen. Six seconds left. He grasped the control handles and twitched them. The tiny golden spark that represented his spacecraft fell away from the green disk of the departure world, inward toward the yellow sun about which all revolved. He had used more than nine-tenths of his fuel and had boosted in the wrong direction. The children around him murmured their displeasure, and a smirk came over Tellman's face. The smirk froze:

As the spacecraft came near the sun, the kid gave the con-trols another twitch, a boost which - together with the gravity of the primary-sent the glowing dot far out into the mock solar system. It edged across the two-meter screen, slowing at the greater remove, heading not for the destina-tion planet but for the intermediary. Rosas gave an low, involuntary whistle. He had played Celest, both alone and with a processor. The game was nearly a century old and al-most as popular as chess; it made you remember what the