Brian Gordon

Slyd game

How could I own a programmable calculator for years and not teach myself to program it? Of the hundreds of BASIC programs that I've keyed in throughout school, this is probably the most interesting.

Slyd is a game inspired by a particlarly devious puzzle in the point-and-click adventure game Machinarium. Play is simple:

  1. Select any square on the grid to start.
  2. Slide in any cardinal direction, leaving filled-in spaces in your wake, until you hit a wall or a previously-filled-in space.
  3. Repeat step 2 until you're confined and thus unable to make a move.

It may be easier just to watch a few seconds of somebody playing the puzzle: link.

Gameplay thumbnail - click to view animation
Click to view animation.

The goal is to fill in every space on the board. Despite their small size, puzzles in this format can be made surprisingly difficult. When solving the built-in level 3 or level 4 I always have to resort to a brute-force search. Interestingly, once you know the solution it's hard to see why the puzzle was difficult in the first place.

Levels are randomly flipped and rotated before loading so that it's difficult to memorize the solutions. Every rotate/flip possibility can be generated with only 0 to 1 horizontal flips and 0 to 3 clockwise rotations.

A built-in level editor allows players to create their own puzzles and save them to a persistent level catalog for later play. Slyd levels are represented by a single integer, so friends can easily share levels across calculators by entering the code at a prompt.

Animation 1: Graphical level catalog generated from this list.
Animation 2: Example use of the built-in level editor and quicksave.
Animation 3: Saving a level to the catalog and then playing it.

A Unicode transliteration of the tokenized BASIC source is available below. The original uncompiled 89p files, suitable for running on a TI-89 or emulator, can be downloaded here: (zip)

The easiest way to play slyd yourself is to install TiEmu and import the programs found in the zip archive. You will need to have the TI-89 operating system handy; this can be downloaded from TI's website.