Requirements: Rank 3 in Mind over Mind.
Affected Area: Up to one creature per rank in Mind over Mind.
Duration: 1 second.
Range: All targets must be within 10 feet per rank in Mind over Mind.
Mental Distraction creates a temporary distraction in the target’s mind. The target experiences the distraction as a brief noise, such as a footstep or breaking glass.
The noise can take any form desired by the psychic, but can never be made so loud as to cause the target discomfort. The origin of the noise is similarly controlled by the psychic, and is under no range constraints, since the noise actually exists only in the minds of his targets.
You should also note that this example not only provides a loose coupling between the Mentalist class and the Mental Distraction ability. It also provides a loose coupling between Mentalist and any other class granting the Psychic Discipline of Mind over Body (by virtue of the Prerequisites needed to obtain the Mentalist class).
Known Uses
Dungeons & Dragons v.3.5 uses Loose Coupling to specify the “Feats” that a character may possess (see the Gifts pattern). The number of Feats that a player may select for his character is dependent on a combination of his character’s level (see the Level pattern) and his class (see the Class pattern). There is no niche protection of abilities granted through this relationship, as the character’s level, an aspect common to all characters, acts as the relationship intermediary. However, some niche protection is provided by Prerequisites listed on the Feats themselves, such as a requirement of “12th
-level Caster.” The loose coupling is somewhat tarnished by the fact that some of the character classes explicitly limit the selection of “Bonus Feats” (additional Feats granted by a class selection) to those on a given list. Aside from this discrepancy, the classes and feats do not otherwise directly reference one another and therefore remain true to the Loose Coupling pattern.
RIFTS relates character classes to skills (see the Class and Skills patterns) using the Loose Coupling pattern, although you have to really be looking for it to spot it.
“Occupational Character Classes” (O.C.C.’s) bestow “O.C.C. Skills” that are directly listed in the class description, which is a form of “tight coupling.” However, classes also have “O.C.C. Related Skills” and “Secondary Skills.” These skills are selected by the player from various “Skill Categories” such as “Communications,” “Mechanical,”
“Technical,” and others. Although these categories frequently reference specific skills directly, they just as often appear with the descriptors of “Any” or “None.” The descriptor of “None” means that the player cannot select any skills from this skill category if he chooses the class for his character. However, the descriptor of “Any”
means that the player may choose any of the skills in the category, with the restriction that he is limited to a total number of skills over all categories.
This “Any” modifier is a well hidden example of Loose Coupling. In effect, it grants characters gaining the class an anonymous gift (see the Anonymous Rule and Gift patterns) allowing him to choose any skills in the specified skill category. By implication, all skills falling within a skill category require this anonymous gift as a prerequisite before a character can select them. The class and skill category are therefore related through this anonymous gift, which acts as the intermediary between the two. The loose coupling becomes obvious after noticing that the class does not restrict characters to a subset of the category, so the game author is free to create new skills in that category in subsequent supplements to which previously written classes automatically gain access. Similarly, the writer can create new classes in later
supplements that access any skill categories he desires merely by allowing the class to grant the appropriate anonymous gifts.
Structural Patterns (Modularity) 157
Modularity
Intent
Boil each rule down to a single basic concern that it addresses. In other words, separate each concern into its own separate rule and give each its own unique name.
Also Known As
Don’t Repeat Yourself (DRY)
Related Patterns
Anonymous Rule, Loose Coupling
Motivation
The Modularity design pattern splits different concepts out into separate rules. It is the antithesis of the Anonymous Rule design pattern. Its goal is to clarify the game’s overall structure by giving each individual piece its own label. A game designer can thereby clearly see the components that make up his game. This may give the game designer insight into useful abstractions combining many disparate rules into fewer more general ones. In this way, a game can often be simplified and actually reduce its overall rule count. Modularity also frequently shortens the game text by allowing complex rules containing similar concepts to be broken down into simpler rules that merely reference common concerns. By splitting out a common issue into its own separate block, the concern can simply be referenced rather than have its text repeated in many places. This makes a game easier to modify and maintain, because an
alteration to a concept requires a change in only one place. Finally, modular games are often easier to understand because the reader does not have to expend much effort in mentally identifying and separating important concepts into discrete elements. That work has already been done for him.
Applicability
The Modularity design pattern applies to any game where reducing overall complexity is an important concern. If layout and smooth text flow is a higher priority, you may want to consider the Anonymous Rule design pattern instead.
Consequences
Perfect modularity can result in an excessive number of individual text blocks unless careful attention is given to identifying useful abstractions combining similar issues into fewer more general rules.
Implementation Concerns
You can go a long way in modularizing your game by using the DRY principle of software development. Anytime you find yourself repeating something you’ve already written, split it out under its own heading and give it a name.
Samples
A game providing descriptions of various monster types might include the following description:
Zombie
A zombie is a member of the walking dead, a soulless, undead human that has risen from its grave to shamble aimlessly through the night. Its eyes always gaze
downward with a glassy blank expression. This unconcerned stare is perhaps its most terrifying aspect, as the monster will rend and tear the flesh of anyone interfering with its nightly patrol without so much as an upward glance to indicate an awareness of its victim. Even as a zombie is disemboweled and dismembered, its stony countenance never wavers.
Like all undead, zombies are Immune to Mental Spells, are Susceptible to Holy Water, and have an Aversion to Sunlight.
In this account, the first paragraph is mere description. There is nothing in the text that affects the mechanics of the game. However, the second paragraph (italicized) is a rule that would greatly benefit from being split out:
Zombie
A zombie is a member of the walking dead, a soulless, undead human that has risen from its grave to shamble aimlessly through the night. Its eyes always gaze
downward with a glassy blank expression. This unconcerned stare is perhaps its most terrifying aspect, as the monster will rend and tear the flesh of anyone interfering with its nightly patrol without so much as an upward glance to indicate an awareness of its victim. Even as a zombie is disemboweled and dismembered, its stony countenance never wavers. Zombies have the standard strengths and weaknesses possessed by all undead (see The Perks and Banes of Undeath).