The tragedy of Willy Loman, and to a lesser extent his children and the way that he passes his own set of expectations and delusions on to them, is something that is gradually brought before the audience as they watch the play unfold. It is only as they listen to Willy's claims of how much he has made on his latest trip, and how this amount steadily falls to the ever-compliant Linda, that they recognise they are witnessing a man who is not honest with himself and cannot admit that he is a failure as a salesman. Tragedy is something that is highlighted through symbolism, as key symbols such as seeds are central to the growing realisation of Willy of the failure that his life has been. Note for example what he says to Stanley at the end of Act II after his argument with Biff:
Nothing’s planted. I don’t have a thing in the ground.
Symbolically, seeds here refers to Willy's growing recognition that his life is not going to add up to anything and he will leave no tangible proof of his success or existence when he dies. His pottering around in his garden and buying seeds is a recognition both of how his own life has been a failure, but also how the lives of his children have been failures (by Willy's judgement). He panics, recognising he doesn't "have a thing in the ground" because he implicitly identifies that the success he has constantly striven for in his life has eluded him. Tragedy is something that surfaces gradually in this play and is therefore presented in a range of different ways.