** Understanding things by their properties
(Channel: 1. Television that can be referred to by channel--Television with channels, simple)
Understanding channels (a number) in the names of televisions.

We might want to allow every television to be tuned to a channel (a number property) which the player could refer to, so that 

	WATCH CHANNEL 13
	TURN OFF CHANNEL 4
	
would be directed to the appropriate television object, if any television is turned on and tuned to the correct station. We might now write:

	{*}"Channel"
	
	A television is a kind of device. A television has a number called the channel. Understand the channel property as referring to a television. Understand "channel" as a television.

	The Office is a room. The widescreen TV is a television in the Office. The fifties TV is a television in the Office. 

	Changing the channel of it to is an action applying to one thing and one number.

	Understand "tune [something] to [number]" or "change channel of [something] to [number]" as changing the channel of it to.

	Check changing the channel of something to:
		if the noun is not a television, say "[The noun] cannot be tuned to a channel." instead.

	Carry out changing the channel of something to:
		now the channel of the noun is the number understood.
	
	Report changing the channel of something to:
		say "You tune [the noun] to channel [number understood]."

	Instead of examining a television:
		if the noun is switched off, say "[The noun] is currently turned off." instead;
		let the chosen channel be the channel of the noun;
		if the chosen channel is a current channel listed in the Table of Television Channels:
			choose row with current channel of the chosen channel in the Table of Television Channels;
			say "[output entry][paragraph break]";
		otherwise:
			say "Snow fills the screen of [the noun]."
	
	Table of Television Channels
	current channel	output
	0	"The screen of [the noun] is completely black."
	4	"A gloomy female news anchor describes the latest car bomb in Baghdad: 104 dead today, and no sign of change."
	5	"A couple of contestants in spangled scarlet outfits are performing an energetic paso doble."
	13	"On-screen, Ichiro is up to bat with one man on second and no outs."
	
	Test me with "change channel of fifties tv to 4 / x channel 4 / switch on fifties / x channel 4 / switch on widescreen / tune fifties tv to 5 / x channel 5 / x fifties tv / x channel 4".