On Calvary, there were three crosses. The middle was Jesus, and then two thieves/revolutionaries.

One chided Jesus and challenged him to come down off the cross if he was really the messiah while the other acknowledged Jesus was the only one among them that was innocent.

Three crosses, then, could represent a decision needing to be made. You either sacrifice yourself, acknowledge there are those who have sacrificed for your sake, or get pissy with those who are literally dying for you.