Chapter 9: Props: Food, Clothing, Money, Toys, Books, Electronics
9.8. Simple Machines

The "device" kind provides for the simplest form of machine: one which is, at any given moment, switched on or switched off. Inform looks after this state, but leaves it to us to make the machine actually do something:

The air-conditioning unit is a device in the Florist's Shop. The air-conditioning is fixed in place and switched on.

Every turn when in the Florist's Shop:
    if the air-conditioning is switched off, say "You worry about the cut flowers in this jungle-hot air.";
    otherwise say "There is an low susurration from the air-conditioning unit."

One primary dictionary definition for a machine is "an apparatus using or applying mechanical power and having several parts", and we often use the "part of" relationship to build machinery. Control Center provides a neat way to display the component parts of a machine to the player who examines it.

One component almost always part of an electrical machine is the (literal) switch, lever or button to control whether they are switched on or off. In Model Shop just such an on/off button is automatically made part of every device.

While an electrical device has only two states, a mechanical machine might have many, and for these the best approach is to define a kind of value naming the possibilities: see Signs and Portents, where the states are the possible destinations pointed towards.

Perhaps stretching the definition of "machine", What Makes You Tick demonstrates a fishing pole which the player can put together from several pieces.

* See Bags, Bottles, Boxes and Safes for a safe that can be dialed to different combinations

* Example  Control Center
Objects which automatically include a description of their component parts whenever they are examined.

** Example  Model Shop
An "on/off button" which controls whatever device it is part of.

*** Example  Signs and Portents
Signpost that points to various destinations, depending on how the player has turned it.

* Example  What Makes You Tick
Building a fishing pole from several component parts that the player might put together in any order.