Polyball!

Another weekend with beautiful weather, another reason to frolic in the park instead of blogging. It's nice to relax.

Except that I was relaxing with Erik and his bocce ball set, and as a couple of engineers we can't leave well enough alone. We experimented with some variations, and I'm proud to introduce a new game — polyball!

Equipment for two players:

• Eight similar balls of two distinct colors, one for each player.
• One smaller ball of a different color (the palino).

The object of the game is to earn points by throwing balls to form triangles that contain the palino. Players may choose the game-ending score. The playing field may be of any surface and size (a park is nice) and the balls of any size and weight and surface (bocce balls are nice).

I recommend bringing a tape measure or long piece of string or laser pointer or something of that nature, to make the sides of triangles easy to visualize.

Rules:

• All balls must be thrown from approximately the same location.
• All throws, including the palino, must initially land at least five feet from the thrower.
• If the palino is thrown short, re-throw it. If a regular ball is thrown short, it is disqualified and ignored.
• Pick a player to begin by throwing the palino. If it lands in a location where it is difficult to see, it may be moved slightly.
• Same player throws their first ball, and throws alternate between players until all balls are thrown.
• Players may not move to examine the field until after all balls are thrown.
• Each player's four balls (A B C D) form four triangles on the field: ABC, ABD, ACD, BCD. Score one point for each triangle that contains the palino, unless an opponent's ball is also contained. (Opponent's ball "disrupts" the triangle.)
• The area contained by the triangle shall be judged in the most generous way, from the outside edges of the balls.
• The triangle contains the palino if any portion of the palino is within it.
• An opponent's ball disrupts a triangle only if it is entirely contained within it.
• In subsequent rounds, alternate the player who throws the palino.

Implied rules:

• More than one player may score in a round.
• Your ball may hit the palino and/or other balls, moving them.

Of course we may tinker with these rules. An earlier variant included points for having the palino along the line between only two balls, and we briefly considered special scoring for containing the palino within a convex quadrilateral.

Have fun!