Feedback and Control Examples

Feedback and control models focus on how reinforcing and balancing loops shape system performance. They demonstrate the push and pull between growth processes and stabilizing forces that aim to keep things on track.

By tweaking parameters you can see how the same structure can lead to runaway escalation or steady regulation. These examples are foundations for understanding thermostats, project management, and many biological processes.

Select an example to explore it in the playground.

Beginner - Introductory Models

Fishery Simulation

A fishery simulation of stocks, flows, and feedback loops managing fish populations.

Level:Beginner

populationresource-managementsustainabilitymanagementecosystemstocks-flowsreinforcing-loopbalancing-looprenewable-resourcequota-policy

  • Stocks:population
  • Flows:births, quota
  • Feedback Loops:reproduction (reinforcing), quota (balancing)
  • Probes:population, quota, gap_to_capacity, extracted_total

Goal-Seeking Decay

A goal-seeking decay simulation modeling exponential approach toward a target.

Level:Beginner

decaygoalbalancing-loopexponentialcontrolfirst-order-dynamicstime-delay

  • Stocks:level
  • Flows:approach_rate
  • Feedback Loops:goal-seeking (balancing)
  • Probes:level, approach_rate

Logistic Growth

A logistic growth simulation of population increase with saturation.

Level:Beginner

populationcapacitynonlinear-dynamicsreinforcing-loop

  • Stocks:population
  • Flows:growth
  • Feedback Loops:reinforcing adoption, saturation constraint
  • Probes:population, growth

Savings vs Credit-Card Debt

A savings vs debt simulation comparing compounding interest effects.

Level:Beginner

debtreinforcing-loopexponential

  • Stocks:savings_balance, debt_balance
  • Feedback Loops:compound interest on savings (reinforcing), compound interest on debt (reinforcing)
  • Probes:savings_balance, debt_balance

Thermostat Simulation

A thermostat simulation showing balancing feedback and time delays.

Level:Beginner

controltime-delaybalancing-loop

  • Stocks:indoor_temp
  • Flows:heat_gain, heat_loss
  • Feedback Loops:controller chasing set-point (balancing), high gain overshoot (reinforcing)
  • Probes:indoor_temp, heater_on
Intermediate - Classic Dynamics

Antifragile System

A simple antifragile system simulation where each failure reduces the probability of future failures.

Level:Intermediate

reinforcing-loopreliability

  • Flows:failure
  • Feedback Loops:learning from failure
  • Probes:failure, failure_rate, total_failures

Dynamic Difficulty Adjustment

Adaptive encounters that track win rate to keep players challenged.

Level:Intermediate

gameplayreinforcing-loopbalancing-loopadaptivegame

  • Stocks:skill, difficulty, retention
  • Flows:practice gains, difficulty adaptation
  • Feedback Loops:skill improvement (reinforcing), challenge tuning (balancing)
  • Probes:skill, difficulty, win_rate, frustration, retention

SIR Model with Vaccination

An SIR vaccination simulation modeling epidemics with optional vaccination.

Level:Intermediate

populationreinforcing-loopbalancing-loopcontrol

  • Stocks:susceptible, infected, recovered
  • Flows:infections, recoveries, vaccinations
  • Feedback Loops:disease spread (reinforcing), herd immunity (balancing)
  • Probes:susceptible, infected, recovered

Sleep Debt Simulation

A sleep debt simulation tracking caffeine, sleep patterns, and debt buildup.

Level:Intermediate

debtreinforcing-loopbalancing-loop

  • Stocks:sleep_debt_hours
  • Feedback Loops:coffee reduces sleep (reinforcing), circadian pressure triggers sleep (balancing)
  • Probes:sleep_debt, subjective_energy
Advanced - Complex Simulations