CreatePolarArc

// Creates polar arc coordinates with given x0, y0 center coordinates, radius, start angle(polar degree north = 0),
// end angle, number of segments.
function createPolarArc(xO,yO,r,startAngle,endAngle,stepSize)
{
	var ring = [];
	ring.push([xO,yO])
	var cartesianStartAngle = 90 - startAngle;
	if(startAngle > endAngle)
	{
		cartesianStartAngle = (360 + cartesianStartAngle)%360
	}
	var cartesianEndAngle = 90 - endAngle;
	var angleStep = (cartesianEndAngle - cartesianStartAngle)/stepSize;
	console.log(angleStep);
	var currentAngle = cartesianStartAngle;
	var radianConstant = Math.PI/180;
	while(currentAngle != cartesianEndAngle)
	{
		var x = xO + r* Math.cos(currentAngle*radianConstant);
		var y = yO + r* Math.sin(currentAngle*radianConstant);
		ring.push([x,y]);
		currentAngle += angleStep;
	}
	var x = xO + r * Math.cos(cartesianEndAngle*radianConstant);
	var y = yO + r* Math.sin(cartesianEndAngle*radianConstant);
	ring.push([x,y]);
	ring.push([xO,yO])
	return ring;
}

createPolarArc(0,0,10,30,60,10)
createPolarArc(0,0,10,30,120,10)
createPolarArc(0,0,10,30,210,10)
createPolarArc(0,0,10,30,330,10)
createPolarArc(0,0,10,330,30,10)
createPolarArc(0,0,10,210,30,10)