For more rainbows checkout DIY Rainbow Crossings.
On our return home there were more rainbows, solar rainbow fairy lights (still up since xmas because that's how we roll) and a beautiful bunch of rainbow roses (gifted from mum a week ago and still going strong).
I watched this video clip with my children this week and asked them if they knew what it was about. The middle one nodded knowingly and said "gayness", I had to laugh. After growing up with two awesome gay aunties, its really just love to them, they don't judge who it should be between, they don't even notice. The children were horrified to hear that some people don't like gay people, and that same sex couples aren't allowed to get married in Australia. You might have said some people have purple blood to explain the incredulous look of on their faces.
I hope you're inspired to sketch a rainbow, we had soooo much fun.