Teaching-mechanic library

living_marketplace · economics · simulator.predict

Concept: Supply & demand

Player does: Shift supply or demand; predict the new price and quantity

Breaks: Higher prices increase demand

Higher prices reduce quantity demanded along the demand curve; only a shift of the whole curve changes demand itself.

price_shock · economics · tuner.formula

Concept: Elasticity

Player does: Change the price to hit target revenue given elasticity

Breaks: Raising prices always raises revenue

Whether a price rise raises revenue depends on the good's elasticity, since demand may fall enough to offset the higher price.

opportunity_fork · economics · tuner.optimize

Concept: Opportunity cost

Player does: Split a fixed budget between two upgrades; name what you gave up

Breaks: Free things have no cost

Opportunity cost is the value of the best alternative given up, which exists even when no money changes hands.

two_nation_trade · economics · tuner.optimize

Concept: Comparative advantage

Player does: Allocate workers in two nations, then trade to beat going it alone

Breaks: A country better at everything gains nothing from trade

Comparative advantage means both countries can gain from trade by specializing where their relative opportunity cost is lowest, even if one is better at everything.

purchasing_power_world · economics · tuner.formula

Concept: Inflation

Player does: The same coins buy less each year; compute the real price

Breaks: Inflation raises every price by the same percent

Inflation is an average across goods; individual prices rise by different amounts, some more and some less.

hidden_spillover · economics · simulator.predict

Concept: Externalities

Player does: Your factory's costs land on neighbors; predict the true social cost

Breaks: The market price captures every cost

An externality falls on people outside the transaction, so the market price can miss part of the true social cost.

one_more_unit · economics · tuner.optimize

Concept: Marginal thinking

Player does: Produce until marginal benefit meets marginal cost

Breaks: Decisions depend on totals, not margins

The best decision compares the marginal benefit and marginal cost of one more unit, not the totals.

crowded_factory · economics · tuner.optimize

Concept: Diminishing returns

Player does: Add workers until the next one adds less than she costs

Breaks: More workers always means proportionally more output

Diminishing returns mean each added worker eventually contributes less extra output than the one before.

gdp_sorter · economics · sorter.bins

Concept: GDP components

Player does: Sort transactions into C, I, G, NX, or not counted

Breaks: Buying a used car counts toward GDP

GDP counts newly produced goods and services, so a resale like a used car is excluded.

policy_levers · economics · sorter.bins

Concept: Fiscal vs monetary policy

Player does: Assign each lever to the central bank or the legislature

Breaks: The president sets interest rates

Interest rates are set by the central bank's monetary policy, while the legislature controls fiscal policy like spending and taxes.

business_cycle_wheel · economics · sequencer.cycle

Concept: Business cycle

Player does: Turn the wheel through expansion, peak, contraction, trough

Breaks: Recessions come out of nowhere

Recessions follow the business cycle's contraction phase, which typically follows a peak of overextended growth.

money_multiplier · economics · simulator.reach_state

Concept: Money creation (textbook model)

Player does: Set the reserve ratio so deposits expand to the target

Breaks: Banks keep every deposit in the vault

Banks lend out most of a deposit and keep only a fraction in reserve, which is what expands the money supply.