bezierCurve in HTML5 making a puzle shape

I am trying to make a jigsaw puzzle game with different types of shapes using bezierCurve. I made it like this. http://ift.tt/1GYtFvX

Now If I want to change the shape of the pieces I need to modify this part -

 outside: function(ctx, s, cx, cy) {
            ctx.lineTo(cx + s * .34, cy);
            ctx.bezierCurveTo(cx + s * .5, cy, cx + s * .4, cy + s * -.15, cx + s * .4, cy + s * -.15);
            ctx.bezierCurveTo(cx + s * .3, cy + s * -.3, cx + s * .5, cy + s * -.3, cx + s * .5, cy + s * -.3);
            ctx.bezierCurveTo(cx + s * .7, cy + s * -.3, cx + s * .6, cy + s * -.15, cx + s * .6, cy + s * -.15);
            ctx.bezierCurveTo(cx + s * .5, cy, cx + s * .65, cy, cx + s * .65, cy);
            ctx.lineTo(cx + s, cy)
        },
        inside: function(ctx, s, cx, cy) {
            ctx.lineTo(cx + s * .35, cy);
            ctx.bezierCurveTo(cx + s * .505, cy + .05, cx + s * .405, cy + s * .155, cx + s * .405, cy + s * .1505);
            ctx.bezierCurveTo(cx + s * .3, cy + s * .3, cx + s * .5, cy + s * .3, cx + s * .5, cy + s * .3);
            ctx.bezierCurveTo(cx + s * .7, cy + s * .29, cx + s * .6, cy + s * .15, cx + s * .6, cy + s * .15);
            ctx.bezierCurveTo(cx + s * .5, cy, cx + s * .65, cy, cx + s * .65, cy);
            ctx.lineTo(cx + s, cy)
        },

But I am new to this BezierCurve so can anyone guide me what should be the value to make this kind of shape.

Now the shape is like this ..