Take this pair of todo lists, in which toggling a todo sends it to the opposite list. In the real world, objects don’t behave like that — instead of disappearing and reappearing in another place, they move through a series of intermediate positions. Using motion can go a long way towards helping users understand what’s happening in your app.

Find the element on line 65, and add the send and receive transitions:

    in:receive="{{key: todo.id}}"

Now, when you toggle items, they move smoothly to their new location. The non-transitioning items still jump around awkwardly — we can fix that in the next chapter.