function step(){
Array.from(document.querySelectorAll("#nodes > [class^='head']")).reduce((p, c) => p.y1.baseVal.value > c.y1.baseVal.value ? p : c).dispatchEvent(new MouseEvent('click', {
'view': window,
'bubbles': true,
'cancelable': true
}));
}
setInterval(step, 5);