Connect-A-Sketch is a design tool that lets you create clickable prototypes from your wireframes and sketches. Its website displays a compact, streamlined, inspirational sign-in form: all the fields are incorporated in a gray arrow element laying on a textile pattern background. The log-in button, arrow-shaped too, stands out in the whole composition and enhances the feel of dynamism inherent to the whole log in box.

Unfortunately Connect-A-Sketch is currently in closed Beta: hope the open sign-up will come very soon.