Build a small d3.js interface

Implementing the concept of direct manipulation for ordering. Given five rectangles, they have the same width, but different in height. You need to design direct manipulation on the rectangles, so you can order them by height. Implement your design with D3. In the webpage, you can only show five rectangles, without any other UI widget. Regarding to the development part, you should use good software engineering practices. Comment your code, use consistent formatting, use meaningful variable names, separate etc.