[caseyryan]

набросал по-бустрому. Примерно так.

package
{
	import flash.display.Sprite;
	import flash.events.TimerEvent;
	import flash.utils.Timer;
 
	public class CornerTimer extends Sprite {
 
		private var _timer:			Timer;
		private var _corners:		Array	= [];
		private var _cornerOffset:	int 	= 50;
 
		public function CornerTimer() {
			_timer = new Timer(250);
			_timer.addEventListener(TimerEvent.TIMER, onTimer);
			_timer.start();
			var c1:Corner = new Corner();
			c1.x = 100;
			c1.y = 100;
			addChild(c1);
 
			var c2:Corner = new Corner();
			c2.x = 100 + _cornerOffset;
			c2.y = 100;
			addChild(c2);
 
			var c3:Corner = new Corner();
			c3.x = 100 + _cornerOffset;
			c3.y = 100 + _cornerOffset;
			addChild(c3);
 
			var c4:Corner = new Corner();
			c4.x = 100;
			c4.y = 100 + _cornerOffset;
			addChild(c4);
 
			_corners.push(c1, c2, c3, c4);
		}
 
		private function onTimer(e:TimerEvent):void {
			var highlightIndex:int = _timer.currentCount % 4;
			var allHighlighted:Boolean = true;
			for each (var corner:Corner in _corners) {
				if (corner.highlighted == false) {
					allHighlighted = false;
 
					break;
				} 
			}
			if (allHighlighted) {
				for each (corner in _corners) {
					corner.highlighted = false;
				}
				_timer.reset();
				_timer.start();
				return;
			}
			_corners[highlightIndex].highlighted = true;
 
		}
	}
}
 
import flash.display.Sprite;
 
internal class Corner extends Sprite {
 
	private var _highlighted:Boolean = false;
 
	public function Corner() {
		drawBlack();
	}
	private function drawRed():void {
		graphics.clear();
		graphics.beginFill(0xFF0000);
		graphics.drawCircle(0, 0, 10);
		graphics.endFill();
	}
 
	private function drawBlack():void {
		graphics.clear();
		graphics.beginFill(0x000000);
		graphics.drawCircle(0, 0, 10);
		graphics.endFill();
	}
	public function set highlighted(value:Boolean):void {
		_highlighted = value;
		if (value) {
			drawRed();
		} else {
			drawBlack();
		}
	}
 
	public function get highlighted():Boolean {
		return _highlighted;
	}
}