| Chapter 9: Time |

| 9.11. Future events

We often want to arrange for something to happen at some point in the future. Here is yet another timepiece:

> An egg-timer is in the Chamber. "A plastic egg timer in the shape of a chicken can be pressed to set it going." Instead of pushing the egg-timer: say "It begins to mark time."; the egg-timer clucks in four turns from now.

> At the time when the egg-timer clucks: say "Cluck! Cluck! Cluck! says the egg-timer."

The event here is called "the egg-timer clucks". It only happens if we instruct so, which we do by writing

> the egg-timer clucks in four turns from now

meaning four turns after the turn in which the egg-timer is pushed. We could alternatively describe this future moment as something like "in 18 minutes from now", or "at 4:15 PM".

If we know in advance what time we want something to happen, we can more simply write:

> At 4 PM: say "The great bells of the clock tower chime four."

(Note that in either case such rules begin with the word "at": they are the only rules allowed to begin with the word "at".)

114
| Example MRE Hunger that eventually kills the player, and foodstuffs that can delay the inevitable by different amounts of time.

115
| Example Empire A train which follows a schedule, stopping at a number of different locations.

116
| Example Scheduling an eclipse To schedule an eclipse of the sun, which involves a number of related events.

First we define the events, and then we create a phrase to schedule them: When the penumbra appears: say "The sunlight dies away to an eerie, brownish penumbra." When the eclipse begins: say "The moon passes across the disc of the sun, plunging the world into darkness."; now the Chamber is dark. When the eclipse ends: say "The moon passes away from the sun, and a gloomy penumbral light returns."; now the Chamber is lighted. When normal sunlight returns: say "The sun shines once more bright in the sky, not to be eclipsed again on this spot for another thirty-seven years." To schedule an eclipse for (totality - a time): the penumbra appears at two minutes before totality; the eclipse begins at totality; the eclipse ends at three minutes after totality; normal sunlight returns at five minutes after totality. Now we make use of the new phrase: When play begins, schedule an eclipse for 3:27 PM. We shall see much more about creating phrases later. Their advantage is that they enable a complicated sequence of operations to be given a meaningful name, and that they can be re-used many times as needed.

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