Find Dr. Orangreen

As I explored Central in HK, I noticed these capsule stickers everywhere. I accepted it at first, thinking it was a pretty cool sticker with its pop of green and orange that cleverly interacted with the space. But after while, it became quite exhausted and started to bug me. It makes me wonder what the meaning it is behind it. The only thing that comes to mind is some sort of indication that a 'drug' can be purchased at this spot - just like in 21 Jump Street.