If you use a static shape, it has a function called .setSkin. Take a look at base/data/shapes/environment. Notice the base.LCD.png, blue.LCD.png, and green.LCD.png?
When the lcd.dts (the numbers you see on the bedroom clock and kitchen stove) is created, it automatically applies base. If you call .setSkin(blue); on it, it'll use blue.LCD.png.
Just not sure how you get it to recognize the .LCD. part as the skin it's supposed to use.