Thoughts on a Clock

"Thoughts on a Clock" was a poem by Eric Ritchie Junior. Extracts of it went,

And now it's time for one last bow

Like all your other selves

Eleven's hour is over now

The clock is striking twelve's.

This was included in at least one of the Christmas crackers that Linda bought for Christmas 2013, where she was invited to a Christmas dinner at Clara Oswald's place and supposed to get to know her boyfriend. Linda wanted something new and something different from the jokes which normally were inside Christmas crackers, so she bought Christmas crackers which had poems in them.

Clara brought the cracker with her to the town Christmas, opened it with the Eleventh Doctor and revealed extracts of the poem. The Doctor, who had hoped for a 'Knock, knock' joke, failed to realize its meaning in the circumstances and said that he didn't get it. (TV: The Time of the Doctor)