My favorite metaphor in Tuesdays with Morrie is the story above the wave. It's a metaphor that uses part-to-whole. Waves are the part; the ocean is the whole. The story is analogous to humans who mistakenly think their deaths are the end of life.
Morrie compares humans to waves. A wave may think it is going to die when it crashes on the beach. It doesn't realize that it's part of the ocean.
Most humans, in their linear thinking and self-absorded lives, think they are headed one-way alone toward death. Little do they realize that they live on in the memory (ocean) of others. In other words, a human is part of humanity, and even though we may physically die, humanity lives on.
"Okay. The story is about a little wave, bobbing along in the ocean, having a grand old time. He's enjoying the wind and the fresh air -- until he notices the other waves in front of him, crashing against the shore
" 'My God, this is terrible,' the wave says. 'Look what's going to happen to me!'
"Then along comes another wave. It sees the first wave, looking grim, and it says to him, 'Why do you look so sad?'
"The first wave says, 'You don't understand! We're all going to crash! All of us waves are going to be nothing! Isn't it terrible?'
"The second wave says, 'No, you don't understand. You're not a wave, you're part of the ocean.' "