Chapter 22

The machine in one breath

Dan: it's a four-stroke. Intake (coin comes in and authorizes), compression (handle stroke stores energy), power (kicker fires, reels spin, clock times the stops), exhaust (payout and return home). One cycle per pull, and every stroke sets up the next one. The handle is the camshaft — one input that sequences everything.

Matt: it's a single function call. play(quarter) — validate input, allocate, run a randomized process with a timer, evaluate the result against a lookup table, return the payout, and clean up. If cleanup doesn't run, the next call fails. Our missing click was a cleanup bug.

Both of us: the whole machine is six systems that hand off to each other in a fixed order.

flowchart TB
    subgraph AUTH["1 · The bouncer — coin authorization"]
        A1[Coin head] --> A2[Escalator] --> A3[Detector] --> A4[Handle unlocked]
    end

    subgraph INV["2 · The teller — coin inventory"]
        C1[Routing point] --> C2[(Payout tube)]
        C2 -->|overflow| C5{Splitter}
        C5 -->|a share| C3[(Jackpot — progressive)]
        C5 -->|the rest| C4[(Cash box)]
    end

    subgraph DRV["3 · The camshaft — handle & operating fork"]
        R1[Handle] --> R2[Operating fork]
    end

    subgraph SPIN["4 · The engine — reels & clock"]
        R3[Kicker] --> R4[Reels spin]
        T1[Clock released] --> T2[Stops drop 1-2-3]
        T2 --> R4
    end

    subgraph COMP["5 · The punch-card reader — hammers & holes"]
        P1[Code discs] --> P2[Hammers / fingers] --> P3[Payout levers] --> P4[Slides]
    end

    subgraph OUT["6 · Cleanup — payout & reset"]
        O1[Quarters metered] --> O4[Cup]
        O2[Jackpot trip] --> O3[Trap door] --> O4
        O4 --> O5[Everything home. Handle relocks. The last click.]
    end

    A3 --> C1
    A4 --> R1
    R2 --> R3
    R2 --> T1
    R2 --> P4
    R4 --> P1
    P4 --> O1
    P3 --> O2
    C2 --> O1
    C3 --> O3

Nothing in it is electric. Levers are the logic gates, springs are the defaults, cams are the sequencer, a governed gear train is the clock, holes in discs are the data, slide travel is the number, and gravity is the bus that moves the coins around.

2.1 The whole cycle as a timeline

sequenceDiagram
    participant C as Coin system
    participant H as Handle
    participant O as Operating fork
    participant R as Reels
    participant T as Clock
    participant P as Hammers & slides
    participant J as Jackpot
    participant X as Reset

    C->>H: one quarter, one pull
    H->>O: stroke
    O->>R: cock and fire the kicker
    O->>P: position the slides
    O->>T: release the clock
    T->>R: stop 1 … stop 2 … stop 3
    R->>P: discs presented to the hammers
    P->>P: which hammers drop?
    alt ordinary win
        P->>P: meter N quarters from the tube
    else BAR BAR BAR
        P->>J: trip the cabinet lever
        J->>J: trap door dumps
    else nothing
        P->>P: no slide selected
    end
    O->>X: return stroke
    X->>P: slides and hammers home
    X->>T: clock home
    X->>J: advance the jackpot reset
    X->>C: escalator steps, detector resets
    X->>H: handle relocks — CLICK