An Explantaion...

There are four classes of 'key' Bronze, Silver, Gold, and Skeleton...

Bronze keys come in two types: Type 1 can unlock any normal locked door on on the same level where they are found, basement, ground, upper story, or attic. This will lead to a new 'room' and the door remains unlocked thereafter, leading to new rooms which randomly periodically change if the door is closed without a 'token rack' (more on that later) at which point it vanishes. They also can lock a presently unlocked door if it lacks a token rack, automatically changing it's destitution if it is unlocked again. Type 2 unlocks or unlocks one specific door as many times as required, and are considered almost worthless because the chances of you ever finding the door it works on are so remote. You can distinguish the two types because the Type 2 keys look like modern keys while Type 1 look like old school keys. Type 1 Bronze keys are the most common and least valued.

Silver Keys are much rarer and more valuable they come in three types: two just like bronze keys but they open 'special doors' with Silver instead of brass, bronze, iron or steel locks. These rooms are the ones in which you will find the best salvage, including large amounts of food and the rare high TL items, but also will contain the most dangerous opponents. The other type 'Type 3 Silver Keys', work like a combination of the best features of Type 1 & 2 Bronze keys, opening any normal door on thee level where they are found and never vanishing, and can be identified because they are not normal keys at all, but rather silver 'key cards' which you touch to the lock to open it.

Gold Keys are very rare, intensely valuable, and highly sought after, and come in two types. 'Type 1' Gold keys are Gold Key-cards which work like a type 3 silver key but on both normal and 'special' doors. Type 2 Gold Key's are the most highly sought keys that a normal person will EVER see, because while while once they are used they only lock and unlock ONE door forever after, the door they unlock is the special kind that leads into potential colony! These keys are oversize childlike 'keys' made of solid gold, and to find one is the life's ambition of many's the savager. People will die for an unused Type 2 Gold Key, or kill for it, but the furor that will arise is as nothing compared to that inspired by the discovery of...

Skeleton Keys: There are only a double handful of real skeleton keys known and proven to exist anywhere: though counterfeits are frightfully common. Each Skeleton key is unique, looking like one of those old school keys with the notches and pins made of blackened cold iron, with a handle carved in the shape of the skeleton of some kind of creature. Skeleton Keys can lock or unlock ANY door, even if they have a 'rack' installed: and they seem to be indestructible: they can be damaged just like any piece of ironmongery but if broken the parts fly back together again and reattach seamlessly while if melted or vaporized the largest remaining part of the key 'regenerates' the missing segments while the other parts have no further powers. The known Skeleton Keys are as follows: Human*, Dog/Wolf**, House Cat, Tiger, Monkey, Rat, Fish, Rabbit, Snake, and Pig, and that is also the order in which they were discovered. According to myth there are exactly 33 real skeleton keys in the universe, and if all of them are found and brought together they will open a door which leads to a room where lairs the ultimate monster, and if that creature is defeated it will grant the bearers of the 33 keys their heart's desire. These 10 keys are confirmed and documented, but no one can agree what the 'other 23' keys are, or how many have been found so far.
*(The Skeleton is Female and 'Negroid' in her early 20s by the morphology of the bones: it also is the most thoroughly examined and documented of 'The Skeleton Keys'...)
**(There is some argument about which creature the skeleton on the handle of this key comes from, even 200 years after it's discovery.)

Among the other contenders are: human 2 (adult male), human 3 (gender neutral child), horse, bull/ox, sheep, goat, lobster/shrimp, crab***, spider, scorpion***, cricket/locust/grasshopper, swan, eagle, raven/corbie/crow, bluebird, cardinal, crane/heron, demon/devil, angel, dragon, hydra, grick, racoon, ferret/weasel, bear, tortoise/turtle/terrapin, crocodile/alligator, dolphin, oyster (with pearl)***, snail, nautilus, rhino, elephant/mastodon, lion, hyena, sloth, platypus, elf, dwarf, orc, tyrannosaurus, pterodactyl, brontosaurus, vilociraptor, triceratops, and stegosaurus...
***(These keys are highly disputed: some people consider them 'confirmed and documented', since there has recently been video of people using them on the internet just like the 10 other 'confirmed' keys, but other people say it was faked because the first 10 known keys were all of vertebrates, it has been so long since a 'new' key was discovered, and there have never been so many findings of 'new' keys so close together temporally...)

Other than the three keys marked with a triple asterisk above, all of which have been rumored for a decade and more but only 'confirmed' within the past 2 years, no new keys have surfaced for over 100 years, and many claim that 'The Legend of the 33 Skeleton Keys' is a myth, a fantasy concocted by those who wish for a grand adventure, an overarching meta-narrative to the world that simply doesn't exist. For others this legend is gospel, a penultimate truth which gives their lives meaning, and there are those that will kill and die for their belief in the legend. Entire Cults and Religions go to war over the validity of this narrative, and the results of it coming true if they DO believe in it... Some say it would usher in the end of days, while others claim it's result would be a perfect world where everyone lived happily ever after, and still others say that it would cause BOTH or have stranger ideas about what would happen: and a few state that it already HAS, several times, each completion of 'The Quest' causing the world to be destroyed and rebuilt to make the people's wishes come true, with no one in the rebuilt world remembering that 'The Quest' had been completed and the keys all being 'lost' once more...

When a true Skeleton Key is found it 'bonds' to the first person to use it to lock or unlock a 'special' door or the door of a 'colony', thereafter while bonded it cannot be removed from the possession of the person whom it is bonded to so long as they live, and grants them some kind of special 'gift' based on what type of creature's skeleton is on the handle: as well as having a restriction on who can make it work and bond to it based on that same criterion. For most of the 'documented' keys not all of these pieces of information are known, but a few are: for example the 'human' skeleton key can only be bonded to by a woman: or at least someone who's 'soul' is female, someone who feels like they SHOULD be female, a person with a female 'gender identity' and in the cases where it is found or acquired and used by someone with that criteria who is stuck in a male body it FIXES that little mistake. The 'gift' it grants is that it's bearer will learn the "true heart's desire" of anyone they willingly have sex with: which some bearers consider more of a curse: and if they can give or have given the person that thing which they secretly desire above all other things that person will become their willing ****.

The only other key for which both the condition and gift are known is that of the Dog/Wolf. To be able to use and bond to that key a person must have had a pet dog or wolf which they truly cared for and kept from the time it was a puppy to the time it died, either of natural causes such as disease which they could not have stopped, even though they tried, or which they put down themselves when it was so old and in pain that killing it was the compassionate thing to do. It's 'gift', and this one's status is less disputed, is that they have a unique power and intuitively know three facts at all times: where the nearest dog or wolf is and the path to get to them through presently stable doors or inside a 'colony': where the nearest person other than themselves for whom that dog or wolf would be a good owner is and the path to get to them: and where the nearest sire or dam with which that dog or wolf would have strong and viable offspring is and how to get to them. The unique power they have is that by deliberately, willingly, and personally feeding a dog or wolf which has been neutered or spayed a piece of blood sausage made from their own blood they will cause that dog or wolf to regenerate it's sexual organs, and be, at least temporarily, at peak reproductive capacity.

While there are rumors about what the other known keys require, and some have their powers or part of their powers known, such as the 'Snake' Key which makes it's bearer immune to any known venom, other than their shared ability to lock or unlock any door even if it has an active 'Token Rack' installed, the requirements and powers of most of the 'confirmed' Skeleton Keys are unknown, though speculation and theories abound.

Now at last: we come to the matter of 'Windows'.

Unlike the operating system found on some computers, true 'windows' consist of three parts, an image, a frame, and shutters. All four must be installed onto an outer wall of a colony and then closed up. When this happens they morph into a glass door looking out on the vista from the 'image' which is locked with a golden chain and padlock. They can only be opened with Type 2 Gold Key or Skeleton Key, at which point the image and door vanish replaced by either a giant room containing the area that was visible through the door, artificially lit and with a holographic covered ceiling, and possibly walls and floor, or a an entrance into another 'mansion', or an immense blank room such as the interior of the kind of hangar where you would park a Airbus A380 for servicing. Careful placement and choice of 'windows' is key to the continued prosperity of a colony, because all areas within a colony follow euclidean geometry, and it can be very difficult to keep the colony from becoming 'bound up' where you cannot successfully install and open any more 'windows' to allow it to expand.

'Images' are wallpaper or large decals depicting a 'tromp ole' scene of such things as a country lane, mountain vista, dock on a lake, window into a vineyard or garden, or new hallway, and they are rare and highly sought. There are rumors of sets of magic paints that in the hands of a skilled artist can duplicate the effects of an 'Image', and though some videos of this being done have surfaced no one in the region you start in has ever personally seen such things.

The 'frame' is an actual window frame with intact glass or large glass pane, which must be placed over the appropriate part of the wallpaper to appear to 'look out' into the Image and locked or sealed shut, then the rest of the wallpaper painted over.

Once you do that you have 1 week to put a set of be-spelled curtains or actual 'shutters' over the window frame to complete the magic and cause it to transform into a full 'window' which can later be 'unlocked' to expand the colony.

You also must make sure that the 'window' is installed into the appropriate area of a mansion: a mountain vista would need to be on the third floor, while a country lane or woods scene must be placed on the first, at ground level.

Leaders of a colony would be well advised to only install a new 'Window' when they have everything they need to make the magic work correctly already put together, including the 'Gold Key' they need to unlock it, because there are many horror stories of what happens if a finished but un-opened window is broken: everything from unleashing monsters from beyond time and space to causing the electricity and water in the colony to cease working, to far stranger things: but almost all the tales agree that whatever happens it spells the doom of the colony.

Everyone around the table is looking impressed, and I smile, as the world starts to take on substance more than just a book in my spirit:

"Whoa, I have got to say this is certainly an original idea son, but what about those 'racks' you have been referring to?" My dad asks, and I smile.

"Glad you asked!" I respond before launching into the next part of my description.