function play(audioCtx, output, timeStep, freqencies) {
let currentTime = audioCtx.currentTime + 0.5;
for (let index = 0; index < freqencies.length; ++index) {
const oscillator = audioCtx.createOscillator();
oscillator.connect(output);
oscillator.frequency.value = freqencies[index];
const startTime = currentTime + index * timeStep;
oscillator.start(startTime);
oscillator.stop(startTime + timeStep);
}
}