HTML

<div id="mygraphiccontainer"></div>

CSS

#mygraphiccontainer {
    top: 20px;
    left: 20px;
    position: relative;
    width: 680px;
    height:500px;
}
.example {
    background: url(../assets/graphics/img/curtain.png) no-repeat center;
}

Javascript

Create a Graphic instance

var mygraphic = new Y.Graphic({render:"#mygraphiccontainer"});

Create a radial gradient to act as a shadow for the glass.

var mygraphic = new Y.Graphic({render:"#mygraphiccontainer"});
var shadow = mygraphic.addShape({
    type: "ellipse",
    stroke: {
        color: "#ddd",
        weight: 0
    },
    fill: {
        type: "radial",
        stops: [
            {color: "#000", opacity: 0.7, offset: 0},
            {color: "#000", opacity: 0.4, offset: 0.5},
            {color: "#000", opacity: 0.1, offset: 0.7}
        ],
        cx: .6,
        cy: .6,
        fx: 0.1,
        fy: 0.3,
        r: 0.8
    },
    width: 280,
    height: 20,
    x:318,
    y:420
});

Create a rectangle with a linear gradient for the chocolate milk.

var milk = mygraphic.addShape({
    x: 314,
    y: 180,
    type: "rect",
    stroke: {
        color:"#6c3f27",
        weight: 1,
        opacity:0.3
    },
    fill: {
        type: "linear",
        rotation: 0,
        stops: [
            {color: "#d1c4bd", opacity:0.9, offset: 0},
            {color: "#a78c7e", opacity: 0.9, offset: 0.4},
            {color: "#6c3f27", opacity: 0.9, offset: 0.7}
        ]
    },
    width:142,
    height:230
});

Add another linear gradient rectangle for the glass.

var myrect = mygraphic.addShape({
    x: 310,
    y: 110,
    type: "rect",
    stroke: {
        color:"#90ad8c",
        weight: 1,
        opacity:0.6
    },
    fill: {
        type: "linear",
        rotation: 90,
        stops: [
            {color: "#90ad8c", opacity:0.3, offset: 0},
            {color: "#819c7d", opacity: 0.3, offset: 0.8},
            {color: "#40563d", opacity: 0.7, offset: 1.0}
        ]
    },
    width:150,
    height:325
});

Create the linear gradient for the reflection.

var reflect = mygraphic.addShape({
    x: 310,
    y: 113,
    type: "rect",
    stroke: {
        color:"#90ad8c",
        weight: 1,
        opacity:0.0
    },
    fill: {
        type: "linear",
        rotation: 0,
        stops: [
            {color: "#fff", opacity:0.0, offset: 0.2},
            {color: "#fff", opacity: 0.4, offset: 0.3},
            {color: "#fff", opacity: 0.0, offset: 0.4}
        ]
    },
    width:150,
    height:318
});

Complete Example Source

<div id="mygraphiccontainer"></div>
<script>
    YUI({filter:"raw"}).use('graphics', function (Y) 
    { 
        var mygraphic = new Y.Graphic({render:"#mygraphiccontainer"});
        var shadow = mygraphic.addShape({
            type: "ellipse",
            stroke: {
                color: "#ddd",
                weight: 0
            },
            fill: {
                type: "radial",
                stops: [
                    {color: "#000", opacity: 0.7, offset: 0},
                    {color: "#000", opacity: 0.4, offset: 0.5},
                    {color: "#000", opacity: 0.1, offset: 0.7}
                ],
                cx: .6,
                cy: .6,
                fx: 0.1,
                fy: 0.3,
                r: 0.8
            },
            width: 280,
            height: 20,
            x:318,
            y:420
        });

        var milk = mygraphic.addShape({
            x: 314,
            y: 180,
            type: "rect",
            stroke: {
                color:"#6c3f27",
                weight: 1,
                opacity:0.3
            },
            fill: {
                type: "linear",
                rotation: 0,
                stops: [
                    {color: "#d1c4bd", opacity:0.9, offset: 0},
                    {color: "#a78c7e", opacity: 0.9, offset: 0.4},
                    {color: "#6c3f27", opacity: 0.9, offset: 0.7}
                ]
            },
            width:142,
            height:230
        });
			
        var myrect = mygraphic.addShape({
            x: 310,
            y: 110,
            type: "rect",
            stroke: {
                color:"#90ad8c",
                weight: 1,
                opacity:0.6
            },
            fill: {
                type: "linear",
                rotation: 90,
                stops: [
                    {color: "#90ad8c", opacity:0.3, offset: 0},
                    {color: "#819c7d", opacity: 0.3, offset: 0.8},
                    {color: "#40563d", opacity: 0.7, offset: 1.0}
                ]
            },
            width:150,
            height:325
        });

        var reflect = mygraphic.addShape({
            x: 310,
            y: 113,
            type: "rect",
            stroke: {
                color:"#90ad8c",
                weight: 1,
                opacity:0.0
            },
            fill: {
                type: "linear",
                rotation: 0,
                stops: [
                    {color: "#fff", opacity:0.0, offset: 0.2},
                    {color: "#fff", opacity: 0.4, offset: 0.3},
                    {color: "#fff", opacity: 0.0, offset: 0.4}
                ]
            },
            width:150,
            height:318
        });
    });
</script>