This may be the author’s version of a work that was submitted/accepted for publication in the following source: Browne, Cameron (2015) Embed the rules. Game and Puzzle Design, 1(1), pp. 60-70. This file was downloaded from: https://eprints.qut.edu.au/107759/ c Copyright 2015 QUT This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the docu- ment is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recog- nise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to [email protected] Notice: Please note that this document may not be the Version of Record (i.e. published version) of the work. Author manuscript versions (as Sub- mitted for peer review or as Accepted for publication after peer review) can be identified by an absence of publisher branding and/or typeset appear- ance. If there is any doubt, please refer to the published source. http:// gapdjournal.com/ issues/ issue-1-1/ issue-1-1-10-embed.pdf C. Browne Game Design Patterns Embed the Rules Cameron Browne, QUT This article examines the concept of embedding the rules of a game in its equipment, as a general pattern for good game design. Several examples demonstrate the benefits of doing so. An analogy is drawn with the Japanese concept of poka-yoke, or mistake-proofing, in manufacturing design. 1 Introduction to simplify the rules as much as possible, while ensuring that the game remains complex enough HIS series on Game Design Patterns aims to ex- to be interesting. T plore fundamental principles that encourage For example, consider the Heptalion puzzle good game designs. While this term is reminiscent shown in Figure 1, in which the aim is to place of the ‘game programming patterns’ described in the five tiles, each showing a pair of symbols, to the book of the same name [1], its use there refers exactly cover the set of matching symbols on the to software programming practices in video game left [3]. These rules are trivially simple and in- development, whereas a ‘game design pattern’ stantly intuitive; no player who has played the here refers to any practice that encourages good game should ever need to reread them. designs in games and puzzles.1 This first install- ment in the series looks at the concept of embed- ding the rules in the equipment. To ‘embed the rules’ means to use relevant fea- tures of the game’s physical components (board, pieces, environment, etc.), to enforce implicit rules which then do not need to be explicitly stated to players. This might also be described as ‘hiding the rules in the equipment’, or phrased as an apho- rism: hide the forest in the trees.2 Figure 1. A Heptalion challenge and pieces. This approach can have significant benefits Despite its simplicity, this design is actually when designing games, including: simplifying the result of considerable thought and effort by its rule sets; minimising player error; handling de- designer Nestor´ Romeral Andres,´ as described in generate geometric cases; allowing the emergence the article ‘Heptalion’ in this issue. This is a case of implicit strategies; providing tutorial assistance of embedding the rules in the components (i.e. the to players; and so on. These benefits are examined two patterns on each tile must be played as a pair, in the following sections, through example. symbols must match identical symbols, etc.), mak- ing the game so intuitive that misinterpretations 2 Poka-Yoke and mistakes are almost impossible. Romeral Andres´ makes the astute observation Simpler rule sets generally reduce the incidence that this process of mistake-proofing is an instance of player misinterpretation or error – provided of poka-yoke.3 This is a Japanese term that refers to that no crucial information is simplified out! – any mechanism in a manufacturing process that and lead to more conceptually elegant games [2]. helps an equipment operator avoid (yokeru) mis- Simpler rule sets also have the significant ben- takes (poka), by drawing attention to human errors efit of giving the player less information to re- as they occur [4]. In the context of game design, member, allowing them to concentrate instead on poka-yoke can be seen as the concept of reducing strategic planning and actually playing the game, player error, by simply making the equipment rather than the mundane bookkeeping of calcu- not allow such mistakes to occur in the first place, lating which moves are legal or not. The trick is either explicitly or implicitly through its design. 1The concept of ‘design patterns’ was introduced in 1977 by Christopher Alexander in the context of architecture. 2Proposed by Richard Reilly, personal correspondence, 12 June 2015. 3Romeral Andres´ first came across the concept of poka-yoke when researching the asymmetric design of the VGA plug that virtually eliminated incorrect dockings by users. If only the USB design committee had learnt from this lesson! Browne, C., ‘Embed the Rules’, Game & Puzzle Design, vol. 1, no. 1, 2015, pp. 60–70. c 2015 2 Game & Puzzle Design Vol. 1, no. 1, 2015 2.1 Explicit Embeddings Rules can be explicitly embedded in the equipment to achieve poka-yoke (mistake-proofing). Consider Ploy, shown in Figure 2, which is an early exam- ple from 1970 [5]. The markings on each piece act as instructions that indicate direction and distance of travel; each piece can move in the direction of Figure 4. Visual cues on a piece from The Duke. one of its markings, a number of cells up to its total number of markings. Visual cues may also be embedded in the board, to constrain piece movement intuitively. For example, each square in the child’s board game Smess: The Ninny’s Chess [7] is marked with arrows showing valid directions of travel. Similarly, the 1972 game Trippples [6] involves 64 tiles each showing three directions of travel (Fig- ure 5), which the players alternately place in an 8×8 square grid to form the board for each game. However, players’ movements are not decided by the arrows under their own pieces but under their opponent’s pieces instead, in a twist that is both poka-yoke and counterintuitive at the same time. Figure 2. A game of Ploy about to start. Such visual cues have been embedded in the pieces of many games since then. The designs on the Mijnlieff4 pieces, shown in Figure 3, intu- itively indicate where the next player must move relative to the piece just placed: orthogonally in line, diagonally in line, adjacent, or nonadjacent. Figure 5. Directional tiles of the Trippples board. Figure 3. The four Mijnlieff piece designs. Abstract rules involving concepts other than movement can also be semantically embedded in the The 5×5 icon grid embedded in pieces of The equipment, e.g. by stating them on playing cards. Duke,5 shown in Figure 4, explicitly show the There are many examples of this in popular card player what actions each piece can perform, and games such as Magic: The Gathering [6] and Do- where. Navia Dratp [6]6 uses a similar mecha- minion [6] (Figure 6), in which the cards describe nism, while Confusion: Espionage and Deception the actions available to players. Even the Chance in the Cold War [6] subverts this idea by show- and Community Chest cards in Monopoly [6] ex- ing movement rules on the pieces, initially visible plicitly state instructions for the players, which only to the opponent, that must be deduced through they do not need to memorise – or even worry play. about – until each card is drawn. 4http://www.mijnlieffgame.com/welcome 5http://www.catalystgamelabs.com/casual-games/the-duke 6I will use the BoardGameGeek online board game database as a catch-all reference for games mentioned in passing. C. Browne Embed the Rules 3 1 2 3 4 Figure 7. The backs of the first four Tantrix tiles (top) and the first two puzzle challenges (bottom). Figure 6. Dominion card ‘Witch’ by Matthias Catrein, c 2008 Rio Grande. 2.2 Implicit Embeddings The standard deck of 52 playing cards also Rules can also be implicitly embedded in the equip- demonstrate mistake-proofing in their rotation- ment to achieve poka-yoke, typically by the shape ally symmetrical illustrations. Players’ cards are of the board and pieces, without the need for fur- always the right way up in their hands regardless ther visual decoration. of what orientation they were drawn in, otherwise Figure 8 shows a game of Tixel8 in progress. many would be upside down when drawn. Tixel pieces are designed with a circular concavity A superb example of poka-yoke can be found in on one side, so that some can rotate in-place in 45 the puzzle game Tantrix.7 The Tantrix set consists degree increments while others are blocked from of 56 hexagonal tiles showing all ways in which rotating, depending on the placement and orien- the tile sides can be joined by paths of four colours, tation of the surrounding pieces. This mechanism such that each tile includes paths of three different simplifies the rule set and enforces this potentially colours (except for three straight lines connecting confusing constraint in a clear, intuitive way. opposite sides).