There are many competing technologies for light strips. We will limit it to LED types, as incandescent and fluorescent lighting tends to require far more power and are less suitable for these small robots.
The simplest are a set of lights that simply turn on when power is applied. These are of one color only and would not make for great information displays. If you want other colors, you would need to buy another color and attach it to a different output.
A improvement on these are strips that can have a color chosen, but this applies to the whole strip. You could change the color of a whole strip to display information. These require three IO pins per strip. If you wanted more than one color at a time, you would need many pins.
The most useful kind in our case, which we will work with in this chapter, are addressable RGB LEDs. Addressable means...