A list is an odd creature, take 3

I mentioned to my first-year students that a list is an odd creature: it has only a head and a tail, where the tail is itself a creature with only a head and a tail, and so on. I challenged them to produce a picture, and Dan Benveniste came up with this:


I like the recursion, but it's not really a creature, is it? Further attempts encouraged! Previous entries:

• A list is an odd creature
• A list is an odd creature, take 2