Fissionquest: Sokoban in 3D

FissionQuest (and its lite version FissionQuest Lite) present another take on Sokoban-like puzzles (see my earlier posts on such puzzles). This game is like Sokoban in 3D, though you also have to watch out not to fall down to death.

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iEscape: Sokoban on the edge

An interesting puzzle concept is available in iEscape, iEscape LITE, and RabbitEscape (the last one is shown here to the right). They are all from the same developer, and basically just different packages around the same puzzle concept. The puzzles are closely related to Sokoban (see my earlier post on classic Sokoban ports for the iPhone). The difference to Sokoban is, in a nutshell, that the “blocks” to be pushed around are now placed in the edges of the graph, instead of on the vertices. So, one could call this “Sokoban on the edge”-puzzles.

Chip’s Challenge reloaded

Things are moving ridiculously fast in the app store—I hardly can keep up with all the new puzzles becoming available every day! You might have noted that I keep adding updates to previous post when new apps arrive that simply replicate other puzzles (see for example my post on Rush Hour or Lights Out), or when previously criticized omission are added in updates (see for example my posts on Mouse House or Blocked). However, sometimes I will write a new post, when there is too much significantly new that has become available.  

In this post I will revisit the topic of puzzles games that are similar in gameplay to one of those dinosaurs of computer games: Chip’s Challenge (for background, see my previous post on such games).

Lights Out: not straighforwardly sequential removal

In a sequential removal puzzle pieces have to be removed in a sequence. Doing it in the wrong order will lead to a dead end. Lights Out is also a puzzle in which something has to be removed (all lights have to be turned off), and as a user you will perform actions sequentially. However, it turns out after some more pondering over the solutions that the order of actions is not important. So, strictly speaking this is not a sequential removal puzzle, but it definitively feels like one.

Cubes: the SameGame with a twist

There is one more SameGame implementation (besides the numerous ones discussed in my previous post) that I think deserves a separate posting: Cubes. There is also a lite version with only four levels to try it out, and a free ad-supported full version – though this free version does not (yet) seem to be available in all iTunes stores. As one might figure out from the illustration, Cubes is a 3 dimensional SameGame implementation. Although this seems to be just a little step further, this turns out to be a really capturing puzzle with good clarity.

Chain Shot! – the SameGame over and over again

The first kind of sequential removal puzzles that I will discuss is the computer game Chain Shot! and its derivatives. Chain Shot! was developed originally by Kuniaki Moribe in 1985 for the Fujitsu FM-8/7 series, and ported to UNIX under the name of Same Game in 1992 by Eiji Fukumoto. This puzzle is probably one of the most ported/cloned puzzle programs available for computers, known under many different names (see a list of pre-2000 ports on wikipedia). Later, it got ported to Windows Mobile where the same game is known as either Jawbreaker, Bubble Breaker, Bubblet or Bubblets. And now it has come to the iPhone, and again the same game is popping up over and over again. The basic principle is actually really nice (Biedl et al. 2001 is an analysis of its complexity is, showing that it is NP complete), but do we really need dozens of versions of this?

Peg Jump: a primer on sequential removal puzzles

Continuing my survey of sequential movement puzzles in the app store, I will take up sequential removal puzzles in the next few posts. In a sequential removal puzzle, pieces are removed one after another until a particular goal is met, typically the removal of all pieces, or all but one. All sequential movement puzzles, including sequential removal puzzles, can be considered to be mazes, including classic sliding block puzzles and more fancy “hidden” multi-state mazes.

Set: another copyright problem

The game Set (designed by Marsha Falko in 1991) is a very enjoyable and innovative card game, in which the object is to find matching sets of three cards as quickly as possible. The deck of cards consists of 81 cards that are all unique combinations of four characteristics with three different options (3 to the power 4 = 81). For example, in the picture shown to the right, the characteristics are color, shape, shadings, and number of objects. The company Mustang Mobile (run by the Falko family) has the exclusive license for development of mobile versions of this game, but this company has (not yet) released a version for the iPhone. However, their exclusive license does not withhold others to do this (a recurrent problem). The following apps are straightforward implementations of Set for the iPhone (links redirect to iTunes):

Chip’s Challenge: a Sokoban Laboratory

For those of you who like the idea of Sokoban, but find it a bit abstract, Chip’s Challenge is probably a good alternative. The original game was designed in 1989 by Chuck Sommerville for the Atari Lynx (in a sense an iPhone predecessor). In Chip’s Challenge, you guide around Chip McCallahan through a series of increasingly difficult puzzles. Many of the puzzles have Sokoban parts in them, but there are many other additions, like ice for sliding, conveyor belts, floors that only be passed once, and bouncing balls that ask for precise timing.

There are various games in the app store that take more or less direct cues from Chip’s Challenge, although I have no idea whether there are any direct links. None of the games even mention Chip’s Challenge. Only one of the games (Loopy Laboratory) cites Chip’s Challenge so directly that it is clearly inspired by it.

Sokoban: not just sliding, but pushing blocks

In his classic definition of Sliding Block puzzles, Edward Horden explicitly noted that “there must be no requirement that they be pushed or pulled by other pieces.” So, let’s change the topic from sliding blocks (as discussed in the last few posts) to pushing blocks.

The most well-known instantiation of a pushing block puzzle is Sokoban (Japanese for ‘warehouse keeper’), created in 1980 by Hiroyuki Imabayashi. In this puzzle, various blocks must be pushed to their destination in a twisted warehouse. The blocks cannot be pulled, so when a block is pushed into a corner it is stuck, and eventually the puzzle will have to be restarted.

Rubik’s Cube: great apps, but wasted efforts…

Ernö Rubik’s Cube is possible one of the most well-known puzzles of recent years. Almost exactly a century after the 15-puzzle craze of 1880, Rubik’s Cube set off its own craze from 1980 onwards. It’s a fantastically great puzzle (it actually was the puzzle that got me into the hobby of collection, solving and designing puzzles), and now it has come to the iPhone as well. However, it might just as well have passed this opportunity. The iPhone is not the right place for a Rubik’s Cube.

Re-Shuffling Rush Hour

A sliding block puzzle is normally played inside a tray, in which the block can move around orthogonally. How about other possibilities of moving block around? Enter Subway Shuffle: Rush Hour on a graph. Or, as the developer Bob Hearn explains it:

Imagine playing Rush Hour, but make all the cars 1×1 instead of 1×2 or 1×3. But still some can only move vertically, others horizontally. Replace the cars by tokens, red for horizontal, blue for vertical, and put the tokens on nodes of a graph with colored edges: red tokens can only move on red edges, blue on blue. If you use a grid graph, with horizontal edges red and vertical edges blue, then you have 1×1 Rush Hour. If you relax the grid graph constraint, and also allow more colors, then you get Subway Shuffle. These relaxations allow for lots of interesting possibilities in puzzle configuration. It’s also possible to have extremely complicated puzzles in a very small space: I’ve generated some puzzles on small graphs that require over 1,000 moves.

Know How to extend Rush Hour

Things move fast in the app store. I just wrote this summary on Rush Hour puzzles, and then today a new variation becomes available: Know How [iTunes Link]. I have not bought the game (at 3€ I find it too expensive to try it out; hopefully a lite version will become available soon). However, from the description and the other information on the web it is clearly a Rush Hour variant. The block can only slide in the direction of the elongation, and the treasure box has to be moved out to a destination outside the playing field (at the bottom in the screen shot to the right).

Rush Hour

One approach to make sliding block puzzles more complicated is by restricting the movements of the blocks. The most prominent example of this strategy is Rush Hour. In this puzzle, all sliding blocks are rectangles of size nx1. These blocks can only be moved in the direction of the elongation. The original trick to make this restriction transparent to the user is to show the block as cars (hence the name “Rush Hour”). It is then immediately obvious that the car can only be moved forwards or backwards, and not sideways.

Rush hour was invented by Nobuyuki “Nob” Yoshigahara and marketed as a physical puzzle by ThinkFun (formerly Binary Arts). There are at least four implementations of Rush Hour available in the app store (links redirect to iTunes):