What a beautiful line: „Old friends - sit on a park bench like bookends“ (from Paul Simon's "Old Friends", preceding the "Bookends" song). And like acoustic bookends, this brief little guitar theme is opening and closing side one of Simon and Garfunkel's album of the same name. From the time when albums had two sides.
C (I believe)
gCEA (works even better in low G)
The basic theme is really very short. Two lines only, but you can play around with this endlessly, add some embellishments, improvise around the theme, try other voicings (lot of options in the first four bars) etc. Very meditative.
"Preserve your memories. They’re all that's left you" - Unless you have a tab sheet.