That is Silly Balloon wall painted gray with a single block of Silly Pink Balloon in front, painted with shadow paint. There are some more hammered balloon blocks around the lower edge of the cannon to give it the circular shape. My plans are to post an unpainted and de-actuated version of the updated pirate ship during the next week.Could you tell me what material you used for the cannons on the side of the pirate ship in your ocean pylon build? I can't seem to find a circular block like that. Thanks!