Slight correction about the Spongebob one: it does tell us quite a bit about his thinking.
He thinks firmly in the box no matter how he appears on the outside. Given the free opportunity to let his creativity flow he chose to simply make a derivative work that's a near copy of another famous work. And when he receives negative feedback on it it breaks him.
Spongebob's lack of creativity screams incredibly loudly in his version of David.
His pile of rocks from when he actually tried to be creative is a painting into his mind in a beautiful way.
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