Run it twice.
Get the same world.

circuit fleet_heat;

// FLEETS (3.9.5): sixteen cells on a rod. Each keeps its own heat by sending
// it to itself and shares it with its two neighbours; cell 0 is held at 100.
// Messages arrive in sender order, so a cell's own value sits right after its
// left neighbour's.
cell rod(id: float, tick: float) -> float {
    let got = inbox();
    let mine = 0.0;
    gate id == 0.0 then { mine = 100.0; }
    let near = 0.0;
    let count = 0.0;
    gate tick > 0.0 then {
        let me_at = 1.0;
        gate id == 0.0 then { me_at = 0.0; }
        let k = 0.0;
        for v in got {
            gate k == me_at then { mine = v; } else { near = near + v; count = count + 1.0; }
            k = k + 1.0;
        }
    }
    gate id == 0.0 then { mine = 100.0; } else { mine = mine + 0.25 * (near - count * mine); }
    gate id > 0.0 then { send(id - 1.0, mine); }
    send(id, mine);
    gate id < 15.0 then { send(id + 1.0, mine); }
    let words = [];
    gate mod(tick, 8.0) == 7.0 then {
        words = push(words, concat("t", tick));
        words = push(words, concat("cell ", id));
        print(concat(concat(words[0.0], " "), concat(words[1.0], concat(" heat ", mine))));
    }
}

cell main() -> float {
    print("rod of 16 cells, 32 ticks");
    fleet rod cells 16 ticks 32;
    print("cooled");
    output 0.0;
}

circuit sp2;

cell sq(x: float) -> float { output x * x; }

cell worker(tag: string, steps: float, every: float) -> string {
    let i = 0.0;
    let acc = [];
    while i < steps {
        acc = push(acc, sq(i));
        gate mod(i, every) == 0.0 then {
            print(concat(tag, concat(" at ", concat(i, concat(" sum ", total(acc))))));
        }
        i = i + 1.0;
    }
    let last = concat(tag, " finished");
    emit last;
}

cell total(xs: list) -> float {
    let s = 0.0;
    for x in xs { s = s + x; }
    output s;
}

cell parent() -> float {
    print("parent spawns a child");
    spawn worker("child", 300.0, 100.0);
    let k = 0.0;
    while k < 3.0 { print(concat("parent ", k)); k = k + 1.0; yield; }
    output 0.0;
}

cell runaway() -> float {
    let n = 0.0;
    while true { n = n + 1.0; gate mod(n, 500.0) == 0.0 then { print(concat("runaway ", n)); } }
    output 0.0;
}

cell main() -> float {
    spawn worker("w1", 900.0, 150.0);
    spawn worker("w2", 600.0, 200.0);
    spawn parent();
    let v = spawn runaway();
    spawn watchdog(v);
    run_all();
    print(last);
    print("done");
    output 0.0;
}

cell watchdog(id: float) -> float {
    let j = 0.0;
    while j < 2500.0 { j = j + 1.0; }
    print("watchdog steps in");
    kill(id);
    output 0.0;
}