"Witnessed"

The player carries a device called a Trifield Natural EMF Meter. The description of the Meter is "This cost a pretty penny off the internet, but it's worth it: according to the website it has been programmed by PhD physicists to ignore manmade sources of fields and to respond only to paranormal EMF changes.

It also features an optional Tone Alarm, which can be turned on to indicate when readings spike. If the alarm is off, the meter just reads out the magnetic and electric field levels on a scale from 0-100 microteslas, or 0-1000 V/m.

Since both fields are important, you keep the meter set to SUM mode. The meter has its own optional backlighting, so that you can see the reading even if your flashlight is off. Currently it is reading at [meter setting]." A Tone Alarm is part of the Meter. It is a device. The description of the Tone Alarm is "The Tone Alarm will make a noise, if the EMF picks up a spike."

To decide what number is meter setting:
    if the meter is switched off, decide on 0;
    if a ghost is touchable, decide on 35;
    if a ghost is visible, decide on 12;
    decide on 0.

After switching on the meter:
    say "You turn on the meter. The needle steadies at [meter setting]."

Every turn: if the meter setting is greater than 10 and the Tone Alarm is switched on, say "[The Tone Alarm] shrieks."

Thirtieth Street Station is a room. "A huge, high, rectangular room with coffered ceilings, which looks grand but mostly makes you feel lonely and small. There are long benches in rows down the middle of the room, and an information desk with the train times, and a series of ticket windows, none of which matters very much at the moment."

The benches are an enterable supporter. They are scenery in the Station. The information desk is scenery in the Station. Some ticket windows are scenery in the Station. Instead of examining scenery in the Station: say "You're fairly sure that whatever is going on here has nothing to do with [the noun]." Understand "window" as ticket windows.

The mural is fixed in place in Thirtieth Street. "At the north side of the station is a particularly pointless and empty annex to the main room. It is dominated by a huge relief of sorts, and this is what you remember." Understand "metal" or "relief" or "huge" as the mural. The description of the mural is "It is both stylized and confusing, but you think it might be supposed to represent the various tasks and occupations of Philadelphia's population. The portions closer to the ground look as though they have recently been subjected to a light dusting of talcum powder. No unusual prints are evident."

The wind chimes are fixed in place in Thirtieth Street. "Carefully attached to the wall with a piece of duct tape and a hook is a light-weight set of wind chimes. Someone else has been here before you, it seems." The description is "Several of your friends use wind chimes as a sort of ghost alarm, since ghosts sometimes cause very localized movements of air when there is no natural breeze."

A ghost is a kind of person. The pale figure is a ghost.

At 9:03 AM: move the pale figure to the location; say "You shiver with some sort of presence."

Test me with "turn on alarm / turn on meter / z / z / z / x figure".

Time can also be understood as a token, and the time parsed will be recorded as "the time understood". So therefore, if we wish for clocks which may be set:

"Tom's Midnight Garden"

A clock is a kind of device. A clock has a time called the current time. A clock can be analog or digital. The current time of a clock is usually 9:01 AM. The description of a clock is "It shows the time to be [if analog]about [the current time to the nearest five minutes in words][otherwise][the current time][end if]."

Understand "set [clock] to [time]" as setting it by time. Setting it by time is an action applying to one thing and one time.

Instead of setting a clock to something:
    say "[The noun] can be set only to a time of day, such as 8:00 AM, or midnight."

Carry out setting a clock by time:
    now the current time of the noun is the time understood.

Report setting a clock by time:
    say "You set [the noun] to [time understood]."

Every turn:
    repeat with item running through switched on clocks:
        now the current time of the item is one minute after the current time of the item.

The Hall is a room. The grandfather clock is a fixed in place analog clock in the Hall. The travel clock is a switched on digital clock in the Hall. When play begins: now the right hand status line is "[time of day]".

Test me with "examine grandfather clock / set it to midnight / switch it on / wait / wait / wait / examine it / set travel clock to 4:12 / examine it".

Suppose we want to have a pair of linked lenses so that the player can look into one of them and see things which occur in room containing the other lense.

We begin simply with a bit of environment for the player to wander around:

"Ginger Beer"

The Ginger Beer Factory is a room. "In the center of the room is an enormous pot filled with crushed ginger, which seems to be bubbling slightly on its own. The fumes are overwhelming."

The pot is scenery in the Ginger Beer Factory. The description of the pot is "Cast iron." In the pot is a bubbling brew.

Instead of smelling the Ginger Beer Factory: try smelling the brew.

Instead of smelling the brew, say "You blink back tears."

The Storeroom is south of the Ginger Beer Factory. "The walls here are lined with a prodigious number of small, rounded bottles, each with a screw top and a smiling pirate on the label."

The Clippings Room is west of the Ginger Beer Factory. "A clean room lined with steel tables, for preparing ingredients."

Some steel tables are a supporter in the Clippings Room. They are scenery. The description is "They are roughly the size and height of laboratory worksurfaces."

The quantity of dandelion is on the steel tables. The description is "Horrible common weed."

The wooden box is on the steel tables. It is openable and closed. The description is "A large wooden box with a lid, used for ingredient storage. There is a label on the lid."

The label is part of the box. The description is "BURDOCK: the root beaten with a little salt and laid on the place suddenly easeth the pain thereof, and helpeth those that are bit by a mad dog:... the seed being drunk in wine 40 days together doth wonderfully help the sciatica: the leaves bruised with the white of an egg and applied to any place burnt with fire, taketh out the fire, gives sudden ease and heals it up afterwards.... The root may be preserved with sugar for consumption, stone and the lax."

The quantity of burdock is in the box. The description is "It looks like a kind of thistle."

Some bottles are in the Storeroom. They are scenery. The description is "They are smaller than the average bottle, because more potent." Instead of taking the bottles, say "Take one away and the whole lineup will cascade to the floor."

Now for the lenses themselves:

A lense is a kind of thing.

The large end of the telescope is a lense in the Ginger Beer Factory. "There is a large glass lense propped against the wall, in which are reflected all the contents of the room." Understand "glass" or "lense" as the large end.

The small end of the telescope is a lense in the Storeroom. "There is a small glass lense sitting on the floor. Due to some curious effect of the optics, it appears to be giving a view of somewhere else entirely." Understand "glass" or "lense" as the small end. The description is "A gleaming lense about the size of a pound coin."

Here is the critical bit, which needs to be somewhat flexible, since the large end of the telescope could in theory be left anywhere in the game (and should still work).

After deciding the scope of the player while the small end is carried by the player:
    let there be the holder of the large end;
    place there in scope.

Before searching the small end when the small end is not carried by the player:
    say "(first picking up [the small end] and holding it to your eye)";
    silently try taking the small end.

Instead of searching the small end when the player is not carrying the small end:
    say "It's too hard to look through the small end from a distance."

Instead of searching the large end,
    say "You see only your own reflection."

We also want to make sure that the player who looks through the small lense does not see the large lense listed among the contents of the other location:

Definition: a thing is recognizable if it is not a lense.

Instead of searching the small end:
    let the far side be the holder of the large end of the telescope;
    say "You peer into the little lense and through it see, in [the far side], [the list of recognizable things in the far side]."

Test me with "examine lense / south / examine lense / look through lense / north / look through small lense".

And we're done.