0.15 => dac.gain;

SqrOsc a;
SqrOsc b;
SqrOsc c;
SqrOsc d;
[a, b, c, d] @=> SqrOsc oscs[];

LPF lpf => ADSR e => dac;
7000 => lpf.freq;
e.set(10::ms, 500::ms, 0.5, 50::ms);
for (0 => int i; i < 4; i++) {
    oscs[i] => lpf;
}

// play a chord (assumes "osc" and "e" are globals)
fun void playChord( int root, int interval[], float amp, dur T ) {
    // set freq (osc is your oscillator)
    for (0 => int i; i < 4; i++) {
        root + interval[i] => Std.mtof => oscs[i].freq;
        amp => oscs[i].gain;
    }
    // set amplitude
    // open env (e is your envelope)
    e.keyOn();
    // A through end of S
    T-e.releaseTime() => now;
    // close env
    e.keyOff();
    // release
    e.releaseTime() => now;
}

playChord(50, [0, 3, 7, 10], 1, 1::second);
playChord(55, [0, 3, 7, 10], 0.75, 1.5::second);
playChord(57, [0, 3, 7, 10], 1, 500::ms);
playChord(52, [0, 3, 7, 10], 1, 1.5::second);