Philosophical question! The Ship of Theseus is a paradox which raises the following question: if an object has had all it's component parts replaced, is it still fundamentally the same object? What if a ship, after a long period of gradual refurbishing, eventually had all it's parts replaced? Would it still be the same ship? This topic is pertinent to the concept of identity. There are many variations to this, such as Heraclitus's river: "Upon those who step into the same rivers, different and again different waters flow." Hobbes put an interesting spin on it too: what if all the planks from one ship were taken, after being replaced, and used to construct another? Which ship, if any, is the "original?