Before I'm telling you about these tutorial, I wanna ask you something. What is the greatest nature phenomena that going over your head? May be some of you have the same answer as me...It's a rainbow. It's swirling in sky after the rain came. So sweet and so awesome I though. The rainbow is my inspiration here, so I've search a tutorial on youtube which will guide you how to make a swirl rainbom in Adobe Illustrator. Here is the video, hope you like it and useful.