I will reiterate because maybe somone is just too lazy to click the link
https://twitter.com/coin_artist/status/584338579691798529

first tweet:
The painting is a #puzzle, there is 4.87 #bitcoin concealed by this image. Happy #EasterEgg

second tweet right, created day after first one and being reply specifically and only to mentioned first tweet :
The new #bitcoin #puzzle was made possible by @robmyers @MattdeCourcelle and @urbenz.

I don't think you have to be satoshi nakamoto to figure out which "new puzzle" second tweet refers to.