Rough Design - Transformation

As seen in my previous post , I guess you have quite a clear idea on how I'm going to Transform  Mad Hatter's hat into a design of a jewellery box. I'm very pleased with the sketch that I've done so far but i'm still not so sure about the shape of the mirror in the interior of the jewellery box. I might do it in an oval shape to compliment the shape of the lid so they wont clash as in shape.