var dir = 5;//скорость морфинга

var rectWidth = 200;

var ellipse = 0;

var shape = new Shape();

addChild(shape);

addEventListener(Event.ENTER_FRAME, morph);

function morph(event){

        shape.graphics.clear();

        shape.graphics.lineStyle(1, 0, 1);

        shape.graphics.beginFill(0xFF0000, 1);

        shape.graphics.drawRoundRect(0, 0, rectWidth, rectWidth, ellipse, ellipse);

        ellipse += dir;

        if (dir > 0 ) if (ellipse > rectWidth) dir = -dir;

        if (dir < 0 ) if (ellipse == 0) dir = -dir;

}