In the book, La Musica Celata" ("The Hidden Music"), Giovanni Maria Pala, an Italian musician and computer technician, reveals how he uncovered musical notes cleverly encoded by Leonardo Da Vinci in "The Last Supper”.
By placing a musical staff on the painting, the loaves of bread on the table as well as the hands of Jesus and the Apostles can be seen as musical notes. This is consistent with the relation in Christian symbolism between the bread (representing the body of Christ) and the hands (used to bless the food).
Pala wasn't able to decode the message until he tried reading the score from right to left, following Leonardo's particular writing style. This allowed him to find a 40-second “hymm to God", which he feels, “sounds like a requiem that emphasizes the passion of Jesus”.
Going in the other direction, you come up with the message, “Paul is dead”.