Finalist for 2005 About.com Deduction Game Design Competition. The first player places the "head" of the pipe on a 4x4 board; the second player, the "tail" of the pipe. Then each player draws a secret pipeline path between the two, crossing at least three spaces. Each player then marks three spaces of her pipe with holes. By placing and moving injectors of colored liquid, as well as probes, on the board, each player reveals information about both players' pipes. The first player to correctly guess the location of her opponent's three holes wins! (Each time you make a wrong guess, you may not guess again for G turns, where G is the number of wrong guesses you've made so far.)