CORNHOLE - credits, sources, and what is reconstructed ====================================================== THE ORIGINAL ------------ Cornhole is a folk sport with no single author and no publisher. Its origins are contested and undocumented; what exists is its modern CODIFIED form, and that has two rule-making bodies: * American Cornhole Organization (ACO), founded 2005 - "ACO Official Rules for the Sport of Cornhole" (Season 19 edition). The ACO numbers its articles, and this app cites them by number: 1.1 boards, 1.2/1.3/1.4 bags, 1.5 court, 2.1 the toss, 3.1-3.15 gameplay, 4.1-4.5 scoring and formats. * American Cornhole League (ACL), founded 2015 - "Rules & Regulations" and "Equipment, Bags & Boards". The ACL names its rules rather than numbering them, so this app cites them by name: Set Uniformity, Bag Values, Win Condition, Wash/Push, Court, General Bag Parameters, General Board Parameters. THIS IS AN INDEPENDENT REIMPLEMENTATION, written from those two published rulebooks. It is not affiliated with, endorsed by, sponsored by, or connected to the ACO or the ACL. No text, artwork, code, data file or trademark belonging to either organisation is included in this bundle. Board and bag dimensions are facts about the sport; every line of code and every pixel drawn here was written for this app. WHERE THE TWO BODIES DIFFER, AND WHICH ONE THIS APP FOLLOWS ----------------------------------------------------------- front deck height ACL 2.8" +/- 0.5 vs ACO 3" to 4" -> ACL (see below) deck angle ACL 11 deg +/- 0.5 vs ACO does not specify -> ACL (only source) pitch style ACL underhand OR overhand vs ACO underhand -> ACO (the stricter) bag weight window ACL 15.5-16.5 oz vs ACO 15.75-16.25 oz -> 16.0 oz nominal (both) timeouts ACL 4 x 60 s vs ACO 2 x 2 min -> neither (not implemented) the two-faced bag ACL regulates it vs ACO never mentions it -> ACL the hanging bag ACL states 1 point vs ACO implies 1 point -> ACL (explicit) settle window ACL 3 s to retrieve vs ACO scored after 5 s -> ACO (5 s is the bound) busting NEITHER BODY HAS ONE -> no bust The ACL is followed on the board because it publishes front height, back height, deck length AND deck angle - one number more than it needs - which makes its figures checkable against each other. asin((12 - 2.8)/48) = 11.05 degrees, inside its own stated 11 +/- 0.5. The ACO's front height range implies 9.59-10.81 degrees, so the two bodies overlap only in 10.50-10.81 degrees. They agree exactly on: 27 ft front-edge to front-edge (+/- 1/2 inch); a 6" hole with its centre 9" from the top edge, centred side to side; a 12" back deck height; a 4' x 3' pitcher's box; the front edge of the board as the foul line; a 15-second pitch clock; 4 bags each and 8 per frame; 3 points for a cornhole and 1 for a woody; cancellation scoring; and 21 to win with no requirement to win by two. THINGS COMMONLY SAID ABOUT CORNHOLE THAT ARE NOT IN EITHER RULEBOOK ------------------------------------------------------------------- * "Boards are 33 feet apart." Neither body publishes 33 feet, or any figure other than 27 ft front-edge to front-edge. Neither publishes a shorter or junior distance at all. * "You bust if you go over 21." No bust rule exists in either body. The ACL says outright: "A player or team is not penalized for achieving a score over 21 points." * "You get 20 seconds to pitch." Both bodies say 15 seconds. * "Bags are filled with corn." ACO 1.3 mandates "plastic resin/beads which will not breakdown". Whole corn is not legal in either body's competition. * "The fast side and slow side are a rule." Half true, and the interesting half. The ACL's Set Uniformity rule explicitly contemplates a bag with two different materials on its two faces and names them - "a gray suede side and a red duck cloth side" - and requires the pairing to be consistent across a set of four. But NEITHER body says which face is faster, by how much, or prints any coefficient of friction, and the ACO rulebook does not mention bag faces at all (all 786 lines searched). So: the mechanic is rules, the ordering and the magnitude are practice. RECONSTRUCTED - the complete list --------------------------------- NO RULE IS RECONSTRUCTED. Every scoring, foul, turn-order and win-condition rule in the engine carries an ACO article number or a named ACL rule. What is reconstructed is the PHYSICS, because neither rulebook contains a single coefficient of friction, restitution, drag or compliance. R1 mu of the fast (suede) face 0.26 R2 mu of the slow (duck cloth) face 0.42 R3 the assignment of "fast" to suede practice, not rules R4 spread velocity: the impact speed that saturates contact 4.20 m/s R5 resting contact fraction 0.55 R6 deformation-friction coupling 0.35 R7 LAMBDA*, the bridging threshold at the hole 1.35 R8 restitution against the board 0.0 R9 drag coefficient of a flat-flying bag 1.1 R10 bag-on-bag restitution / friction 0.05 / 0.55 R11 where inside the 4' x 3' box the player releases x = +/-0.55 m, 0.10 m back R12 release height 0.62 m R13 the three opponent skill levels tunable, unanchored Both faces' friction must clear one bound that the rules DO imply: ACO 1.1 requires a surface "not so slippery that the bags slide back down the platform", and ACL fixes the deck at 11 +/- 0.5 degrees, so mu >= tan(11.5 deg) = 0.2035. Both do. DERIVED, not chosen: the fill's bulk density. Modelling the flat-laid bag as a 6" square whose corners are pulled in to the ACL's minimum 7.5" flat diagonal gives a footprint of 34.79 in^2, and 16 oz in 34.79 x 1.3 in^3 is 0.612 g/cm^3 - inside the 0.50-0.65 band for bulk plastic resin pellets. The ACL's four independent bag numbers are mutually consistent. THE HOLE-CAPTURE CRITERION IS THIS APP'S OWN -------------------------------------------- No rulebook describes when a bag hanging on the rim falls through, so the criterion here is mine and is stated in full rather than hidden. The contact patch is split by the rim; LAMBDA is the ratio of the toppling moment of the unsupported fill to the restoring moment of the supported fill about the rim, computed from exact closed-form areas and centroids; the bag drops when LAMBDA >= LAMBDA*. One consequence is a check on the criterion rather than a choice: LAMBDA = 1 exactly when the patch's centre sits on the rim, for every deformation state, so LAMBDA* = 1 makes the capture region exactly the 6-inch hole. Also: a rigid 6" square cannot pass a 6" hole at any legal tolerance, so every 3-point score in this sport is a deformation event. WHAT DIFFERS FROM A REAL MATCH ------------------------------ * Singles only. No doubles, no ACO Quads, no ACO Skins. * No pitch clock, no timeouts, no officials. So ACO 3.7's 15-second clock, ACO 3.2's three-strike foot-foul escalation and ACO 3.6's 12-point touching penalty are implemented in the scorer and proved by the test harness, but are not reachable through play. * The bag is released flat and square to the throw, with no spin the player chooses; spin only arises from bag-on-bag contact. * Players do not walk to the far end between frames; the camera stays behind the pitcher and the target board is always the far one. The rules this changes (ACO 3.7's 30-second walk, ACO 4.1's "take score and resume pitching back") are cosmetic here. * The opponent's skill is a Gaussian error model on the same solver the player's aim guide uses, not a model of any real player. BUILT WITH ---------- Hand-written WebGL2 and plain JavaScript. No frameworks, no libraries, no CDN, no network calls, no analytics, no cookies. One localStorage key ("cornhole.v1") holds your match record and your control preferences, on your device only. Sources consulted, all publicly published by the bodies themselves: ACO Official Rules for the Sport of Cornhole (PDF), americancornhole.com/rules ACL Rules & Regulations, iplaycornhole.com/about/acl-information/rules-regulations ACL Equipment, Bags & Boards, iplaycornhole.com/about/acl-information/equipment-bags-boards