Overlap in Hue-Saturation

[gimp-artist]

I'm reading gimp Docs. I attached the part of doc for the overlap in Hue-Saturation where how they explain about it. It was difficult to understand what they mean only by reading it. So I tested overlap for myself. I kindof get the concept of it. However I feel like something missing cause I don't understand what docs say about it. Would you tell me how to get the correct concept of overlap in Hue-Saturation dialog?