ToME WikiMachine aka Foul Factory is a SpecialLevel on DungeonLevel 50 in the dungeon Illusory Castle, created by Lord Dimwit.
Intro
This level isn't designed to kill the player, really, just induce such severe aggravation that their head explodes. There are two parts of it, the "abusive trickery" part that leads the player through a horrendous maze of strategically placed glass walls, illusion walls (they look like walls, but are actually passable tiles), permanent walls, living wall monsters, granite walls that you must dig, and ethereal walls (like permanent walls only invisible, very awful), followed by a Factory stage that follows more traditional patterns of throwing monsters systematically at the player.
Monsters
Tons of golems. They resist cold, poison, probably other things. They're hard to detect by anything but being near them with a light (being cold blooded and all that) but most of them aren't too tough.
Some monsters are (weak) wall monsters. Kill them to walk where they used to be.
Rewards
The goal of Machine, apart from trying to drive the Player crazy with seemingly dead-end paths, is to obtain the rare and wonderful Pair of Metal Shod Boots of the Machine, an artifact powerful yet filled with potentially deadly side-effects...
You also get lots of random items on the floor near the center; more than you might be able to carry. So bring some ID.
Getting around the walls
If you have problems with the ethereal walls, use the '%' command to change the character / tile used for the feature. Type %8NNN and then c or C until you find an appropriate character / tile.
Another option, requiring less technical hassle/skill but not available to all characters, is to use some ingame method of changing floor-tile type. For example, repeated casting of fireflash and firewall, from a spell or a stick, will change illusion walls and normal floor tiles to a smouldering (and thus recognizable) mess and leave the ethereal walls untouched. Obviously you'll want fire immunity if you're doing this, but then by this point in the game you'll probably want it anyway. Be careful if you also use any effect that creates sand, however: sand+heat=glass...
An alternate option to keep track of where you can step is growing trees wherever you step. Trees that will grow elsewhere at the same time indicate places you can step on - etheral walls don't get trees. You can also bring 99 arrows/essences/whatever and drop them where you step so you have a nice map of where you can step. By bringing 2 or more types of junk, you can give them meanings (i.e. places that can be walked on but are confirmed to be a dead end get an arrow, and anywhere you can step on that's not confirmed to be a dead end gets a food ration dropped on it).
Also, etheral walls as well as regular walls become visible when you bump in them; but fake walls and normal floor squares don't because they won't block you. So if you go around without a light then you know that only things that block the way will show up! Just remember you'll have to find out diggable granite squares anyway, but the no-lights trick helps a lot.
The no-light trick also means you won't see golems, and you can't detect them by infravision (they're cold blooded). So be careful and use the light when you must!!