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A sign on the wall reading "No thumbtacks on wall", held up with thumbtacks. A sticky note is on the sign with a question mark, and arrows pointing to the thumbtacks. A sticky note is below that sticky note reading "No sticky notes on signs", also on the sign. A sticky note is on that sticky note reading "Sticky note on sign!", with an arrow pointing to the note it is on. A sticky note is on that sticky note reading "No sticky notes on sticky notes". A sticky note is on that sticky note reading "No purple sticky notes", the note is purple.