Saturday, November 29, 2008

Browser Games 12

Two more browser based games this week. Both are physics based. Both are fun if a little short.


Assembler is a simple 2-D platform game. The object is to build a structure in which the green box (or boxes) is (are) placed in the desired position (or positions). You have to move the various crates and beams and whatnot into position. What makes Assembler special is the accuracy of the physics model. It feels right. It matters how you pick up the boxes with your mouse as they pivot on that point. It also matters how quickly you move them around. The momentum, friction, and water are modeled perfectly. At times this is a frustration as you have to move items around and end up knocking over already correctly placed items. Also, you might know what you want to do, but have to move things out of the way to get there. The levels are well constructed and well paced. This is a great game. The only negative I found is that you have to complete the levels in order. But there are only 18 levels. Once you finish those off, there is Assembler2 which some of the original levels, some reworked levels, and some new levels.

The underlying physics engine used in Assembler is the Box2D engine. It is open source, and I took a peek at the API. It appears reasonably easy to use. Maybe more games will come out using it. A commercial game based on the Box2D engine is Fantastic Contraption. It is more of a The Incredible Machine game.


The goal in Auditorium is to redirect the flow of gas particles so a sufficient number pass through each square. Later, as in the screen shot, the color of the gas matters. As the gas particles pass through a target square, a different sound is produced. As more particles pass through, the bars in that square rise and the sound increases. You need to raise each square to its maximum to complete the level. The resulting final solution is usually audible pleasing.

Each level comes with a few items which you must place. A big part of Auditorium is learning how these items effect the flow of the gas. The simplest are the arrows which redirect the gas. You can place them where ever you want. You can also change the strength of an arrow by increasing or decreasing it radius of effect. You do not get to change the direction though. One trick is that you can peal off part of the gas stream by having an arrow's effect radius intersect only part of the stream.

As you progress, new items appear. It is your job to figure out how they work. Two flaws in Auditorium: levels must be completed in order and some levels require very careful placement. Still, this is great little diversion. The site claims that this is a demo, but it is a very polished game, and well worth playing.

Sunday, November 16, 2008


Title: Quoridor
Author: Mirko Marchesi
License: Commercial Board Game

Author: Martijn van Steenbergen
License: Creative Commons

It has been a while since I did an entry on an abstract strategy game. So, here is a short one on a different two to four person game call Quoridor. I am only going to focus on the two person version.

The rules are very simple. Quoridor is played on a 9 by 9 board. The goal is to get your marker to other side of the board before your opponent does. The twist is that players can place 2-long barriers on the board. Each turn, you can either move your marker one square orthogonally or place a barrier. But you cannot move through a barrier, neither the opponent's barriers nor your own. You have a limited supply (ten) of barriers; use them wisely. There is a restriction on placing the barriers; you cannot place one which completely blocks your opponent from the other side. One final rule: if your marker is next to your opponent, you can jump over your opponent and land on any neighboring square not blocked by a barrier.

What makes Quoridor interesting is learning what makes for a good position. In A.I. lingo, learning a good heuristic. I really enjoyed the learning possess for this game as the obivious heuristics are flawed. First off, being close to the other side of the board is not always the best place to be. If your opponent has a bunch of barriers left in their pool, they can use them and force you backtrack or zig-zag. Next, I thought that having multiple paths to the other side was a good thing. But oddly, due to the rule that your opponent may not cut off all paths, sometimes having only one path is an advantage as your opponent cannot take it away. The other factor is the value of the barriers, the more in reserve the better, but what is the right weighting of these factors?

To start learning the game, you can play against Martijn van Steenbergen java implementation. It has a very clean and intuitive interface. There are four levels of play. The A.I. is not strong, but the SmartBrain 2 level beat me the first time I played due to my lack of familarity with the game. Level 3 plays a better game, but is slower. Level 4 is too slow to be practical. I would say that the A.I. underestimates the value of keeping barriers in its pool.

One observation I have is that the play balancing of Quoridor is spot on. The choice of using a 9x9 board and a pool of 10 barriers seems to be just right. Reading the wikipedia article on Quoridor mentions some previous incarnations of this sort of game. So, these choices are the result of some trial and error. One of those previous games is Blockage. Another vaguely similar game is Camelot, for which a Zillions of Games zrf file is available.

Saturday, November 01, 2008

Puzzle Books

To wind down after a long day, before going to bed, I like to knock off a few logic puzzles. What might frustrate many is calming to me. Ok, I am a bit odd. Over the years, I have purchased many puzzle books which sit on night stand until finished. Here are few of the better ones.

Title: Mensa Exercise Your Mind Math & Logic
Authors: Dave Tuller & Michael Rios

Title: Brainteasers on the Flip Side
Authors: Dave Tuller & Michael Rios

Back with more, Tuller and Rios produce some of the best puzzle around. Each book includes hundreds of puzzles. The puzzle types vary. Each includes some original Tuller-Rios puzzles, see my post on a previous version for some examples. The puzzles are well constructed and challenging. Another thing which might seem silly, but matters: the paper is of high quality. This nice when you have to erase.

In the interest of full disclosure, I know Dave Tuller and have talked to him about his books. He in no way encouraged me to include any mention of his books in this blog.

Title: Jumbo Book of Number Puzzles

This is great puzzle book I got at Costco for $5.49 about a year ago, but I have not seen there in a while. It seems hard to find on-line. WHSmith claims to sell it, but but does not have a picture of the cover and lists the availability as 4 or more weeks which makes me suspicious. If you see it again at Costco, grab it. Grab two, one for you, and one for a friend.

It contains many of the standards: Domino Puzzles, Slitherlink, Sudoku, Mind Sweeper, Mastermind, Hitori, Kakuro. It also includes a couple of new puzzle types. One which I found every interesting is called Piecework. It is a set up as nonogram, however there is not enough information given to solve the puzzle. You have to use the additional constraint that the picture consists of the 12 pentomino arranged in the grid so that no two touch. This results in some brilliant puzzles.

Title: Japanese Logic Puzzles
Author: The Times

Here is a book I picked up on my last trip to England. It is a collection Hashi (aka bridges), Hitori, Mosaic, and Slitherlink puzzles. What really struck me about this collection was the quality of the Hitori puzzles. There are only 30, but they are very well done. I had never given generating Hitori puzzles much thought. Is there no good computer method for generating these puzzles? There are 20 Mosaic puzzles, 75 Hashi, and 75 Slitherlink. The only downside to this book is the paper quality is lower than the others.

Title: KrazyDad Slitherlinks
Author: Jim Bumgardner aka KrazyDad

Free slitherlink puzzles in pdf format. Download, print, and solve. The real find here is the puzzles in different grids. I really found the Penrose Tile puzzles a great twist.