Hypolimnas bolina or Blue Moon butterfly.
The male has three pairs of white spots on the upperside of the wings surrounded by purple iridescence.
Apparently the wings are covered by microscopic scales causing multiple reflections. I noticed they were specially intense when directly under the sun, and this explanation points to the deep blue component of sunlight being amplified. Nature’s design even better than state-of-the-art LED lights!
It is quite friendly, really, allowing me to come closer, and methinks even giving me a wink. 🙂