svg = DOM.svg(300, 200);
const rectGroup = DOM.g();
const rect1 = DOM.rect(20, 20).attr('fill', 'blue');
const rect2 = DOM.rect(20, 20).attr('fill', 'red');
rectGroup.appendChild(rect1);
rectGroup.appendChild(rect2);
svg.appendChild(rectGroup);
slider = html`<input type="range" min="1" max="5" value="1" />`;
mutable resizeRectangles = {
const scaleFactor = +slider.value;
rect1.attr('width', 20 * scaleFactor).attr('height', 20 * scaleFactor);
rect2.attr('width', 20 * scaleFactor).attr('height', 20 * scaleFactor);
};