Some illustrations drown constucted in html/css. They are made from divs, mainly just experiments with border-radius.
Each element in the flower is a div, with position:absolute;. The rainbow is made from 4 divs one inside the other, positioned relative, colors are from border/background/border/background of each div, one inside the other.
Oh, they work in Firefox, Chrome, Safari, and latest Opera. In Internet Exlporer – only if you want to see a square flower and a square rainbow.