An example of associating units of #measurement with light, using the visible light spectrum to describe distances. This example segments the visible light spectrum into 6 different lengths of color, (A rough sketch to illustrate the idea, yellow should be the smallest band).
In this example, we measure E.Coli bacteria, but rather then 2000 nano-meters long, we can say its 200 orange or 25 blue. Because Orange is about 10 #nanometers and Blue is 80. Here we are describing the distance by giving the relationship between Blue and Orange. We are not concerned about #precision, precise measurements , but rather a general approximations as #light is a #gradient of color, lacking defined borders.
