 Let's review what happens when we create a list. The variable words is a reference to the area in memory where the list items are stored. What happens if we assign the list to a new variable? Do we get a new copy of the list? No, we do not. Instead, we get a copy of the reference. The technical term for this is aliasing. Words and words B are aliases for the same list. This has implications. If we change an element of words B and then print the words list, this is what we'll see. Let's show this program in Thani to show that it really works as we say. We'll do an assignment, which copies the reference, then change one of the items in the list that's referred to, and print words to show that both variables refer to the same list. And that's exactly what happens when we run the program. This effect is almost always unexpected and often undesirable. What we would like is a way to get a copy of the contents of the list. Here's the trick. We'll use list slices. Remember how slices work? When we get a list slice, it creates a new list with a new reference. To get a brand new list with all the contents of the original list, we use a slice without any beginning or ending numbers. That makes a new list with all the items in the original. This is called cloning the list, and here it is in Thani. We clone the list here and change an item in the cloned list. Then we print the original list, which remains unchanged, and the new list, which has been modified, and there are the results. And that's how you avoid problems with aliasing by using a slice to clone a list and create a new reference.