Thoughts on a Clock

"Thoughts on a Clock" was a poem by Eric Ritchie Junior. An extract 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. When Clara Oswald brought it to the Eleventh Doctor in the town Christmas, he was hoping for a "Knock, knock" joke, and was disappointed by the bit of poetry. He claimed not to understand it. (TV: The Time of the Doctor)