analog image renderer in that it can visualize a numeric 
  point, but instead of choosing one out of a set of images it dynamically draws the indicator of the value. For 
  example, the pointer can be drawn on a single dial image. To add a new dynamic renderer, add a new subdirectory to 
  the graphics directory and put the static image and an appropriate info file there. Then, add a rendering function to 
  the resources/view.js file. The function must be named according to the name given to the subdirect