Unclosed Puzzles

2016-04-26 Second edition 🙂

Stop press!

Apology: Before I changed this page I called the behavior of some Sokoban clones for bugs. That is not the case but unusual design of puzzles and small differences in interpreting .sok-files that sometimes produce some unexpected results. Choosing the right/wrong skin you can get even more strange results.

You cant take back an email. You cant unpublish a book. But fortunately you can change an internet page. Below the changed page accordingly to the rightful criticism.

Did you know you can design and play a Sokoban puzzle like this, here screendump from YASC ?


The effect is caused by using a skin with the same graphics for floor and background.

Still some unusual puzzles even if you use an other skin:

Now YASC shows the puzzle like this:


And JSoko like this:JSoko13

How does Sokoban++ do?


YSokoban shows the skin as YASC, but comes with a warning:


And that is exactly the case. The playing area is not closed.

Three of the Sokoban clones here closes the puzzle by an invisible wall in one way or another. And treat the puzzle as valid.

The clone has to calculate what a complete blank line between puzzle-elements means. Is it a separation between two puzzles or a separation between two design elements? Not always easy.

As long as you dont make a blank line, you can safely have separate design elements both before and after the area with the Sokoban:


Puzzle designers tend to make a complete wall around their puzzles. Did you ever se one without? So this little quirk (Not bug. I will never use that word again) will usually stay a secret.

Not very fun to exploit either since the fun depends on choosing the right skin and the right Sokoban clone.

Lets have a little fun anyway.

Now an unpublished butterfly. Not an unclosed level as far as I can see.

The clones see it differently:


Sokoban++ a little more conservative:


YSokoban. Floor is always used as background so the puzzle looks as intended but you still get the warning “Unclosed level”:


If I choose the right skin and background my butterfly looks right in any clone:


The first element on a puzzle line has to be a wall or a box on goal. But it is possible to make a blank line inside a puzzle and get a row of floors.

Let me make a muzzle for my peacemaker:


SokobanOnline doesnt allow blocks on goal in the outer wall, so I had to block the muzzle:


More secure that way…

In the end it is only design, not playability. You could use the quirk in your design positively too:

Nobuttom2Who needs a buttomline ? Or a solution 🙂