Prototyping Interface Dimensions

The dimensions of the following prototypes all relate to money in some respect, be it the shape of a credit card, bank note, or implement the same ratio of length to width as a credit card or bank note. This is in an effort to create a subtle connection with money in producing a Chip and PIN device. I have also   experimented with different profiles, concave and convex that work in a more natural swing of the thumb.