This one takes me back to my hippie days. There are several approaches that can be used to create rainbow mandalas, so I will be experimenting with some others and you will get to see the results. For those of you interested in how this is done, I took the photos of nightblooming cactus flowers and desaturated them in Photoshop under layer adjustments. I then went to hue/saturation, checked the colorize box and used the slider in hue/saturation to change the hue. By increasing saturation and darkening a bit, I was able to come up with these vivid colors.