The Rosetta Stone
Based in "X marks the spot" given that it marks to a Stone and this is the most directly related with the paint picture that is given as clue, and some similarity with the previous puzzle.
Rosetta stone is key to solve the problem in the "construction" of the babel tower, I saw another user mentioned as a posibility another stone like "Rosetta Stone" but didn't submit as a solution, see quote
It may be an "x" meaning 10, or it is directing us to a brick/stone. I know a famous "Rosetta Stone" which have ties to languages like the Tower of Babel.