Impossible Levels

[MagiMaster]

I've noticed that many people (inlcuding myself) post levels that they aren't sure can be solved, only to have someone else solve them (usually within a couple days).  It seems to be very hard to make a level that isn't trivially impossible.  So far I've seen three kinds of levels that actually are impossible.

1) Lack of component
1a) Would be solvable if you removed/replaced the antisigns
1b) Too few crates for matchers
1c) No crates of appropriate value

2)Lack of time: A puzzle which cannot be solved without some component being activated twice in between two activations of another component (not counting cargo in fast-adder puzzles)

3)Geometric problems: A puzzle which cannot be solved without two objects occupying the same space.
3a) Blocked target matcher: No matter what pieces are added, some matcher can't be reached
3b)Crate value contradiction (i.e. masixon)
3c)Lack of space: An impossible puzzle which could be solved with paired teleporters to and from corresponding points in a large empty region somewhere else.

4) Randomly impossible: not solveable for all values that '?' cargo can assume
4a) Lack of required value (e.g. '?' turning into '0', while '1' is needed)
4b) Lack of information (e.g. only know 2x and x is needed)

Has anyone made a level that is impossible, but doesn't fall into any of those categories?  I don't have any at the moment, but I'll try and make one soon.

A note on the speed of light and terminal velocity:
Terminal velocity is the fastest an object can move or be moved.  It depends on environmental factors such as how much empty space is available, as well as which object is being moved (a crate can be moved faster than a dozer).  It also depends on the direction the thing is being moved.  For example, the terminal velocity of a dozer moving (straight) upwards is fairly slow (<1) even with infinite space.  Within a finite space, it is (generally) even slower.
The term speed of light comes from work done on cellular automata such as Conway's Game of Life.  It is defined as the fastest that information can be transmitted.  In the Game of Life, c = 1 space orthogonally or diagonally.  Rube and Rubicon are cellular automata (really complicated ones) so the term still applies; however, the speed of light is infinite.  For example, a long line of crates can be pushed and the last one can be moved up or down with pipes.  Of course, an infinite speed of light is unreachable in practice, but the idea is still meaningful.

[Bucky]

There's also a lack-of-information impossible (such as Ternary Queries variant zabanim).

[jnz]

tyfabet may be impossible.  I'm not sure if it falls into one of your categories.

[Bucky]

tyfabet may be impossible.  I'm not sure if it falls into one of your categories.

It's solveable.
pysofac shows the main idea.

[jnz]

It's solveable.
pysofac shows the main idea.

Pretty sneaky.    Nice job.

[geej66]

For a much simpler solution to tyfabet, try bobokot.

[jnz]

For a much simpler solution to tyfabet, try bobokot.

Ouch.  That's embarrassingly simple.  Perhaps samynib is slightly more impossible.
Edit: so much for that idea: sovupoz

[Bucky]

godazut is impossible, but it's purely time-bounded, so it doesn't fit either category.

I'm going to post one with only three crate streams, which should be sovable.

[MagiMaster]

So should lack-of-time and lack-of-information be added to the categories?  If so, how would you define lack-of-information?

Edit: Also, should probabilistically impossible (sometimes impossible) be changed to mathematically impossible (such as a simple divide-by-2 puzzle), or would that be a seperate category?

[Bucky]

So should lack-of-time and lack-of-information be added to the categories?  If so, how would you define lack-of-information?

Edit: Also, should probabilistically impossible (sometimes impossible) be changed to mathematically impossible (such as a simple divide-by-2 puzzle), or would that be a seperate category?

lack-of-time:Solving would require at least one component to be activated more than once in the same tick, or more than once between two activations of certain other components.

lack-of-information:The exact value of a crate on one side of a target matcher cannot be determined;  This is a subcategory of "sometimes impossible"  because it can be solved at least one time in 16.

lack-of-component:A Usually a subcategory of "Trivially Impossible". Example: dyzodyp

[MagiMaster]

I updated the list.  I guess a divide-by-2 puzzle would fall under lack of information.

[Bucky]

About the speed of light:
I thought that this term referred to the maximum speed which information can travel;  By this definition, the speed of light is infinite in all directions, since a bit of information can travel from anywhere to anywhere in 2 ticks by pushing a long line of crates and then sucking the last one up an up-pipe.

[sluutthefeared]

I updated the list.  I guess a divide-by-2 puzzle would fall under lack of information.

Maybe I'm missing something, but I don't understand what you mean here.

[MagiMaster]

About the speed of light:
I thought that this term referred to the maximum speed which information can travel;  By this definition, the speed of light is infinite in all directions, since a bit of information can travel from anywhere to anywhere in 2 ticks by pushing a long line of crates and then sucking the last one up an up-pipe.

Hmm... You could be right, although what about the case where the information is the value of a crate?  Can that information be moved faster than the crate?  Also, if you define c that way, what would you call the maximum speed you could move a single crate around?

I updated the list.  I guess a divide-by-2 puzzle would fall under lack of information.

Maybe I'm missing something, but I don't understand what you mean here.

Since all of the arithmetic in Rubicon is in base-16, the operation of multiplying by 2 is irreversible.  (For example, 1+1=2, but 9+9=2 as well.)  So a puzzle that took a random crate, doubled it and gave it to you to match to the original would be impossible half of the time.  (You'd just have to guess which of the two the original was.)

[sluutthefeared]

Ah, ok. I didn't realize you meant multiplying first. I suppose there's plenty of problems that could be thought up which would be thrown off by the modulo arithmetic.