diff --git a/2016/ruby/day_24.rb b/2016/ruby/day_24.rb
new file mode 100644
index 0000000..778e699
--- /dev/null
+++ b/2016/ruby/day_24.rb
@@ -0,0 +1,130 @@
+class Solver
+  def initialize(maze)
+    @maze = maze
+  end
+
+  def solve(from, to)
+    seen = Set.new(from)
+    queue = [[from, 0]]
+    current = queue.shift
+
+    loop do
+      location = current[0]
+      break if location == to
+
+      seen << location
+
+      neighbors = maze
+        .open_neighbors(location[0], location[1])
+        .reject {|location| seen.include?(location) }
+
+      queue.concat(neighbors.map {|location| [location, current[1] + 1] })
+
+      return nil if queue.empty?
+      current = queue.shift
+    end
+
+    current[1]
+  end
+
+  private
+
+  attr_reader :maze
+end
+
+class Maze
+  attr_reader :locations
+
+  def initialize(input)
+    @maze = Hash.new
+    @locations = Hash.new
+
+    x, y = 0, 0
+    input.chars.each do |char|
+      case char
+      when /\d/
+        @locations[char.to_i] = [x,y]
+        char = ?.
+      when "\n"
+        x = -1
+        y += 1
+      else
+        # no-op
+      end
+
+      @maze[[x,y]] = char
+      x += 1
+    end
+  end
+
+  def [](x,y)
+    maze[[x,y]]
+  end
+
+  def open_neighbors(x, y)
+    [[-1,  0],
+     [ 1,  0],
+     [ 0, -1],
+     [ 0,  1]].map {|dx,dy|
+       [x+dx, y+dy]
+     }.select {|x,y|
+       self[x,y] == ?.
+     }
+  end
+
+  private
+
+  attr_reader :maze
+end
+
+if __FILE__ == $0
+  maze = Maze.new(ARGF.read)
+  solver = Solver.new(maze)
+
+  hash = maze.locations.to_a.combination(2).each.with_object({}) {|(a, b), hash|
+    steps = solver.solve(a[1], b[1])
+    hash[[a[0],b[0]]] = steps
+    hash[[b[0],a[0]]] = steps
+  }
+
+  p maze
+    .locations
+    .map(&:first)
+    .permutation
+    .select {|route| route[0] == 0 }
+    .map {|route|
+      [route, route.each_cons(2).map {|a,b| hash[[a,b]] }.inject(:+)]
+    }.sort_by(&:last)
+end
+
+require 'minitest'
+# require 'minitest/autorun'
+
+class TestMaze < Minitest::Test
+  def test_maze
+    maze = Maze.new(<<-MAZE)
+###########
+#0.1.....2#
+#.#######.#
+#4.......3#
+###########
+MAZE
+    assert_equal [1,1], maze.locations[0]
+
+    assert_equal [[2,1], [1,2]], maze.open_neighbors(1,1)
+  end
+end
+
+class TestSolver < Minitest::Test
+  def test_solver
+    maze = Maze.new(<<-MAZE)
+###########
+#0.1.....2#
+#.#######.#
+#4.......3#
+###########
+MAZE
+    solver = Solver.new(maze)
+    assert_equal 2, solver.solve(maze.locations[0], maze.locations[4])
+  end
+end