Генерирует тень со смещением по кругу

circle_shadow_generator.js

function genCircleShadow(r, items, limit){
	var shadow = [];
	
	limit = (360 / items) * limit;

	for(var a = 0; a < limit; a += (360 / items)){
		var ar = a / 180 * Math.PI,
			x = ~~(Math.sin(ar) * r),
			y = ~~(Math.cos(ar) * r),
			c = "rgba(255,255,255," + (1 - a / limit).toFixed(2) + ")";
		shadow.push(x + "px " + y + "px 0px 0px " + c);
	}

	return shadow.join(",\n");
}