See inside the project then click the green flag. As you can see, a and b are treated as lists. You can see that c looks like a list, but the is-a predicate and add-to command see that it doesn't happen. You can also see that the label for c is in a different relative position than a and b. See if you can figure this one out.data:image/png;base64,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data:image/png;base64,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