function chart(theta) {
const context = DOM.context2d(width, height);
context.fillStyle = "black";
context.fillRect(0, 0, width, height);
const a = 15;
hex.context(context);
context.lineWidth = radius / 3;
context.beginPath();
context.strokeStyle = "rgb(200, 150, 90)";
hex.angle(a).mesh();
context.stroke();
context.beginPath();
context.strokeStyle = "rgb(50, 100, 180)";
hex.angle(a + theta).mesh();
context.stroke();
return context.canvas;
}