Current Junction
playablecurrent_junction · engineering · balance.ledger
Concept: KCL
Player does: Balance every junction: current in = current out
Breaks: Current gets used up at junctions
Kirchhoff's current law says current in equals current out at every junction; none of it is consumed there.
Voltage Loop
playablevoltage_loop · engineering · balance.ledger
Concept: KVL
Player does: Make rises and drops around the loop sum to zero
Breaks: Voltage is the same everywhere in series
Kirchhoff's voltage law says the rises and drops around a loop sum to zero, so voltage drops across each series element.
Network Compression
playablenetwork_compression · engineering · tuner.formula
Concept: Equivalent resistance
Player does: Collapse the resistor network; predict the single equivalent
Breaks: Parallel resistors add up
Parallel resistors combine by reciprocal sum, which always gives a smaller equivalent resistance than any branch, not a sum.
Capacitor Reservoir
playablecapacitor_reservoir · engineering · tuner.formula
Concept: RC charging
Player does: Choose the wait so the capacitor reaches 63% (one τ)
Breaks: Capacitors charge linearly
A capacitor charges exponentially, approaching its final voltage faster at first and more slowly over time.
★ Logic Factory
playablelogic_factory · engineering · builder.circuit
Concept: Logic gates
Player does: Wire gates so the output matches the target truth table
Breaks: You need AND, OR, and NOT to build any circuit
NAND alone is functionally complete, so every logic circuit can be built from NAND gates without AND, OR, or NOT.
State Explorer
playablestate_explorer · engineering · builder.circuit
Concept: Truth tables
Player does: Test every input combination and fill the table
Breaks: Checking a few inputs proves the circuit
A circuit is verified only by testing every input combination in its truth table, not a sample of them.
Grouping Territory
playablegrouping_territory · engineering · builder.tiles
Concept: Karnaugh maps
Player does: Cover the 1-cells with the fewest power-of-two rectangles
Breaks: Groups can be any size
Karnaugh map groups must be a power-of-two size (1, 2, 4, 8…) to correctly simplify the expression.
Signal Railway
playablesignal_railway · engineering · transformer.trace
Concept: Multiplexers
Player does: Set select lines so the right input track reaches the output
Breaks: Select lines carry the data
Select lines only choose which data input is routed through; they never carry the data themselves.
One-Bit Room
playableone_bit_room · engineering · transformer.trace
Concept: Flip-flops
Player does: Predict the stored bit after each clock edge
Breaks: Outputs change whenever inputs change
A flip-flop's stored output changes only at a clock edge, not whenever its inputs change.
Safe Sampling Window
playablesafe_sampling_window · engineering · mapper.number_line
Concept: Setup & hold time
Player does: Place the input transition outside the window around the clock edge
Breaks: Any change before the edge is safe
A signal must be stable through both the setup time before and the hold time after the clock edge to be sampled safely.
Instruction Factory
playableinstruction_factory · engineering · builder.tiles
Concept: Pipelining
Player does: Schedule instructions into stages; count total cycles
Breaks: Pipelining makes each instruction faster
Pipelining raises instruction throughput by overlapping stages; it does not shorten any single instruction's latency.
Datapath Relay
playabledatapath_relay · engineering · sequencer.linear
Concept: Instruction execution
Player does: Route an instruction through fetch, decode, execute, memory, write-back
Breaks: The PC changes only on jumps and branches
The program counter advances after every instruction, not only on a jump or branch.
Memory Distance
playablememory_distance · engineering · sequencer.rank
Concept: Memory hierarchy
Player does: Rank storage by latency and capacity
Breaks: Bigger memory is faster
Memory hierarchy trades capacity for speed: the fastest tiers, like cache, are the smallest.
Path Prediction
playablepath_prediction · engineering · simulator.sample
Concept: Branch prediction
Player does: Guess each branch; watch the pipeline flush on a miss
Breaks: Mispredictions cost nothing
A branch misprediction forces the pipeline to flush and restart, costing real cycles.