$.shape.alignment.x

function update() {
    $.shape.alignment.x="center";
    $.colour.stroke="transparent";
    $.colour.fill="red";
    $.shape.rectangle($.w/2, $.h/2, 10,	10);

	$.shape.alignment.x="left";
    $.colour.fill="blue";
    $.shape.rectangle($.w/2, $.h/2, 30,	30);
}