Great graphic, BellaBoo. That shows the block nicely.
The pattern was made from varigated fabric from the designer that goes from a light to dark value in one piece of fabric. For example, the brown is all one fabric, and every 11 inches it goes from light brown to medium light, then medium dark and finally dark. The pattern says to cut your yardage where the value changes and then cut your strips. So for the sample quilt you would be buying just three varigated fabrics for the blocks (brown, blue, green). But when you cut each fabric apart where the value changes, it functions as four fabrics for cutting your strips.
You can get the same effect by carefully choosing four browns with varying values, four blues, etc. You don't have to use that varigated fabric from the designer unles you are trying to match that pattern exactly.
The photo Susie posted shows what you can do with same pattern concept but build it out with different colors. It looks like there are a lot of ways to play with this block and layout.