one dataset · paper, tables, graph, wiki
simgrammar the grammar of simulation

parts

17 mechanics, as SimCity does them

core · 5

economy & finance

Land value

Each 2x2 block's value falls with distance from the population-weighted center, rises near trees and water, and drops with pollution and high crime, clamped to 1-250.

resources & production

Power grid

Zones must connect to coal or nuclear plants through power lines or adjacent zones; unpowered zones do not grow and lower the city score.

economy & finance

RCI demand

Three valves move by the ratio of projected to actual residents, commerce, and industry plus a tax offset, clamped to +/-2000 or +/-1500 (Micropolis source).

economy & finance

Treasury and budget

Tax revenue is collected periodically from population, land value, and tax rate; police, fire, and road funding fractions scale their effects, and underfunded roads decay.

space & construction

Zoning

The player paints 3x3 residential, commercial, and industrial zones; simulated developers build, densify, or abandon them.

supporting · 12

space & construction

Building placement

governance & policy

Citizen satisfaction

A yearly evaluation turns problem scores into a 0-1000 rating and an approval poll.

risk & failure

Crime and policing

Crime per cell is 128 - land value + density minus smoothed police effect, clamped 0-250.

information & legibility

Data overlays

Map windows show land value, crime, pollution, traffic density, police and fire coverage, and population density.

environment & ecology

Fire spread

environment & ecology

Pollution spread

Industry and traffic write a pollution map that depresses land value and can summon the monster.

risk & failure

Random disasters

Fire, flood, tornado, earthquake, and a pollution-gated monster fire at 1/481, 1/241, or 1/61 per cycle by difficulty.

progression & goals

Scenario objectives

Time-limited scenarios such as Detroit 1972 set a goal to reach before the clock ends, added at Broderbund's suggestion.

logistics & networks

Service coverage

Police and fire stations write funding-scaled effect values to a block map that is smoothed outward.

economy & finance

Taxation

One city-wide tax rate adds a positive offset to demand at low rates and a negative offset at high rates.

logistics & networks

Traffic congestion

Zones generate trips along roads; the resulting traffic density map adds to pollution and complaints.

core loop

zone residential, commercial, and industrial land -> connect roads and power -> RCI demand and land value grow zones -> collect taxes each year -> fund police, fire, and roads -> respond to crime, pollution, traffic, and disasters

design notes

Will Wright grew the game out of the map editor he built for Raid on Bungeling Bay and drew its model from Jay Forrester's Urban Dynamics. The simulation is a set of coarse grid maps (land value, crime, pollution, traffic density, police and fire effect) recomputed in passes, plus three RCI demand valves that integrate city-wide balance; a zone grows when its local score plus the valve passes a random test. The 2008 GPL release as Micropolis made these update rules, including crime = 128 - land value + density - police effect, inspectable.

appears in

the paper, 4 sections · 6 chapters · 6 episodes
paper

1. Introduction

linked in this section of the paper

paper
paper

3. The catalog

linked in this section of the paper

paper
paper

5. The structure of the design space

linked in this section of the paper

paper
paper

Appendix A. Game catalog

linked in this section of the paper

paper
catalog

The catalog

listed with its year, developer, subgenre, and number of mechanics

book
ch 2

Chapter 2. Six layers

linked from the text

book
ch 3

Chapter 3. Old parts

linked from the text

book
ch 4

Chapter 4. Families

linked from the text

book
ch 5
book
ch 6

Chapter 6. Five ceilings

named in the text

book
ch 9

Chapter 9. Vacant lots

linked from the text

book
ep 2

Where the parts came from

on screen at 0:56 a date is a lower bound, 2:53 the founding games

episode
ep 3

Families across genres

on screen at 3:38 odd couples, 4:34 series and descendants

episode
ep 4

Why deep systems are hard to read

on screen at 4:15 expensive and hidden

episode
ep 5

The five ceilings

on screen at 3:26 ticks per second

episode
ep 8

Vacant lots

on screen at 1:12 packages, 7:08 how a lot closes

episode

sources

2
Wikipedia contributors (2026). SimCity (1989 video game). Wikipedia
Will Wright, Don Hopkins (2008). Micropolis: open-source SimCity source code. GitHub (SimHacker/micropolis)

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gacatalog
2026-10-24
reviewed2026-10-24-review-fixesmaintenance