This strategy is great for you when you want to have a lot of visual context and want to quickly identify tasks and projects from one or more smart lists via background color.
In this strategy's settings you can connect smart lists, labels or categories to colors. Then tasks and projects that match those smart lists are shown in that color.
Example: Coloring recurring items
In case you want to easily differentiate between normal and recurring items using background color marker could be a solution. First, you'll have to create a Smart List with Advanced filter set to isRecurring. Doing this selects all recurring items.
Now that you have the smart list, you can add it by clicking on "Add Marker" which will create a new marker that you will connect to this, previously created smart list.