CreateJS の API：quadraticCurveTo

/*quadraticCurveTo() API
*/
var stroke_color = "#ff0000";
var shape =  new createjs.Shape(new createjs.Graphics().beginStroke(stroke_color).moveTo(0, 25).quadraticCurveTo(45, 50, 35, 25).endStroke());
this.addChild(shape);