RubyTree is a simple to use general purpose tree data structure implementation in Ruby. It provides easy access methods for navigating the hierarchy, as well as for accessing the nodes. It also provides ability to marshal the entire tree structure. The library provides a generic tree as well as a binary tree implementation. It is available as a RubyGem or standard Tar/ZIP packages.
Binary Puzzle Solver in Ruby is an automated solver for Binary Puzzles (a kind of logic game) featured on http://www.binarypuzzle.com/. The solver contains an API and a commandline program and explains why it thinks the player should place a 0 or a 1 in the box. Although it contains only a subset of the moves the authors could think of and does not use backtracking, it was able to solve all the puzzles from binarypuzzle.com which the authors tried.