## Monday, June 18, 2007

### Everett Kaser's games

Everett Kaser is the master of deductive logic games. From his lair near Corvallis, Oregon he unleashes a steady stream of clever, addictive puzzlers.

If you've ever tried out one of those pen-and-paper puzzles that has three people, three houses, three jobs, and some clues like “The person who lives in the red house is not a carpenter” you know roughly what the games entail. Kaser has designed his games so that the clues are presented in graphical form, and has blended in visual puzzle elements.

For instance, in Honeycomb Hotel you are trying to determine which of several options belongs in each hexagon in the board; but you are also simultaneously trying to determine a Hamiltonian path that enters the board, visits each hex, and exits. Here's an example of a very simple puzzle with two clues:

Each hex contains its possible options; you can eliminate them as you work through the clues. The central hex's contents have been given. The left clue says that the mouse and the letter H are adjacent and connected by a path. The right clue says that the grasshopper and the letter Y are adjacent but separated by a wall.

There cannot be a path connecting the entrance and exit hexes, because then the path wouldn't visit any of the other hexes on the board. This rules out the possibility of mouse and H being on the right side of the board. Once they are placed, Y is known, which places grasshopper and the rest. Here's a partial solution; can you see how to finish it?

Baker Street, another personal favorite, replaces the Hamiltonian path with a tree and is on a board of mixed squares and hexagons, for more varied connectivity:

My wife and I have spent more time on these games than any other. Free demos are available for everything. Give them a try and see if they are to your taste.