Advanced rulebook

This page has solutions for Prison, Skull House, Tour, and Crushers and mentions some advanced words.

This article lists advanced techniques and tricks that can be helpful when solving levels.

## Prison Trick

Normally if a rule is up against a wall and can only be moved along it, you can't ever break the rule. But if you could move the text onto an object, the object can move along the rule and break it apart from within. This is known as the Prison Trick because in the level Prison, you have to push  onto an object that is  using a second object that is also , letting you break it apart. Of course, this can also be done with any object that isn't solid that can then move or make something else move (using , , , etc).

## Item Duplicating

This technique is commonly called "skullhousing" because it is introduced in Skull House.

Normally when you write  (where  and  are distinct nouns), each  turns into a single . However, if you write  and  simultaneously in the same turn (or any similar construct like ), then you get both a  and a  for each , doubling the amount of objects you had before. This process can sometimes be repeated to make arbitrarily many objects.

If you write , you get a stack of two . See Object Unstacking below for methods to separate them.

Another way to duplicate objects is to stack text, e.g. by writing . If any piece of text in the rule  was actually a stack of the same piece of text, the rule would be parsed multiple times and multiple  objects would be created.

## Text Stacking

Since  is a base rule, overlapping text is difficult. However, it can still be done in a few ways:

* TELE doesn't care if something solid is at its destination. Normally the objects on two TELEs will just exchange places, preventing stacking. But if one of the units has mismatching  with one of the TELEs or there are 3+ TELEs, you can have two different units land on the same TELE and stack them.
* Two pieces of text stack if they simultaneously move onto the same tile. Both moves must be caused by the same kind of initial movement (both  or both ). (Note that ,  and  are direct reactions to movement, and are considered to happen simultaneously with what triggered them, so two text objects being SHIFTed onto the same tile is the same as if two MOVERs pushed two text objects onto the same tile.)
* Text can be created (with , , or ) on a tile that already has solid objects in it just fine. So if  and  is destroyed while being on a piece of text, you will stack  and that text object.
* If you PUSH an object onto a SWAP object, the pusher and SWAP object will overlap. Similarly, if you PULL an object while moving onto a SWAP object, the PULL and SWAP object will overlap.
* can be used to easily stack text since PHANTOM text can still be pushed.
* Text can be stacked if  can be formed with another way to move text.
* With  and paths, it is possible to stack text.
* You can stack text after REVERTing an object that was text.

## Object Unstacking

If two objects of the same kind are on the same tile, it can be hard to separate them. Here are some things you can try:

* While SINK will consume all objects simultaneously when it triggers, OPEN/SHUT being triggered as a reaction to movement will only consume one object.
* If the objects are facing different directions, a rule involving  or  could get them to separate.
* Because of the way the game handles Object Priority, the objects in a stack FALL after each other, allowing you to easily separate them by making them FALL and PUSH.
* Any stack can be separated using the randomness provided by at least three TELE objects or the  and  conditions.
* Objects can also be unstacked via conditional .

## Cyclic Conversions (Tour)

This trick is introduced in Tour. It allows you to have an object that alternates between being  and  for instance. All you need is a rule like . Cycles that undergo three or more conversions before they repeat are also possible. Combining this with the "skullhousing" trick lets you duplicate items every turn.

## Vehicle (Crushers Trick)

If you stack two SHIFT objects on the same tile, then they will move forward each turn. The reason this happens is because the two SHIFT objects queue SHIFT movements for each other simultaneously, then both movements are resolved.

## Update Order Shenanigans

While no puzzle in *Baba is You* requires you to discover the update order between two units to solve it, some strange interactions happen if two simultaneous actions can't be resolved cleanly. Depending on which unit is processed first, different things will happen. Some examples:

* If a unit tries to move to two different places simultaneously, it will move only to the second place – the movement will not be stacked, and any other consequences of the first movement will not be overridden either. For example, if two MOVE units try to push the same PUSH unit, then it will move in the direction of the second MOVE unit's push.
* If two SHIFT units try to act on each other, the earlier SHIFT unit will change everything else's direction to its before anything else happens.
* 'Time Travel Trick': If you destroy a unit and undo its destruction, its update order may have changed. This means that undoing moves can be part of a puzzle's solution! A HOLD object sometimes releases the held object when using this trick, which can be used to cheese 48.

## Parallel Universes

*Main article: Out of Bounds*
When using , an object can go out of bounds. An out of bounds object will get deleted at the end of the turn, but until then, there's a few weird consequences to going out of bounds to the right of the screen. (Objects seem to get stuck when going out of bounds in a different direction.)

The game stores the game grid as a single array with each cell having value y\*width+x. This means that, when leaving off the right edge of the screen, the object will loop around to the left edge of the screen, but one tile lower. (Note that the level width includes the two EDGE tiles, and going on said edges is enough to be considered out of bounds.) Any interaction that looks for other objects on a certain tile is based on this grid instead of absolute position, and so objects can interact. Note that the object that is out of bounds can also interact with things in bounds, but if it creates any new objects (eg. through ) those will also spawn out of bounds and will vanish at the end of the turn.

An object that goes out of bounds and then returns in bounds before the end of turn will not be destroyed.

## Operator Cloning

If an object skullhouses then gets REVERTed, it will get cloned.

## Cursor Riding

If a level has turned into a  object, the  ( by default), can go on it and ride the  object to get to otherwise unaccessible levels (eg. ? and Do it Yourself) as the transformed level still counts as the level.