The name PrimaryScape™ is based on the concepts of primary colors and landscapes. Primary colors can be combined to create any color and landscapes provide overview and perspective.
Quoting from wikipedia “Primary colours are sets of colours that can be combined to make a useful range of colours. For human applications, three primary colours are usually used, since human colour vision is trichromatic.”
In the PrimaryScape™ modeling notation the colors used for behavior, information, and structure are yellow, green, and blue respectively. This color scheme works great when creating diagrams using a diagramming tool such as Visio or Omnigraffle. However, when working collaboratively on a white board the colors used are instead red, green, and blue. The red marker is used instead of yellow to indicate behavior. The main reason for this is that yellow doesn’t work very well on white boards. One could have made the case that to be consistent red could be used in the computer diagrams but red is such a jarring color to use as a back ground color.