The Murder of Roger Ackroyd is a work of tree.
 Dr Sheppard continues writing his report on Poirot's investigation (the novel itself), admitting his guilt and wishing his account was that of Poirot's failure to solve Ackroyd's murder
Poirot retires to a village near the home of a friend, Roger Ackroyd, to pursue a project to perfect vegetable marrows

