The following morning, I found my mentor, Professor Annity, busily cleaning up after what looked like a series of curious experiments. As I entered the lab, she fixed me with a familiar sort of excited, faintly frenzied expression, and ushered me across to the workbench, upon which lay five similar-looking bundles, each slightly different in shape, each covered over with a cloth.
“Well! I may have worked all night, but... as you will learn, success comes with perseverance. Behold, my latest invention!” She gestured to the fifth bundle. “Ah! But before I unveil it, let us first examine failed experiments #1 - #4, the better for you to understand my processes.”
Fighting back my natural curiosity I nodded assent, and the good Professor indicated the first bundle. I peeked beneath the cloth. “This one, frankly, was a mistake... The second, well, as you can see - it’s even less interesting. Moving quickly on...” She picked up the third bundle and handed it to me. “This one is lighter than the others.” I nodded again - indeed, it did appear lighter. I replaced it on the bench. “So far, though - unremarkable. Experiment #4 though, I think you’ll agree, was an astonishing attempt!”
And indeed, dazzled though I was by the Professor’s ingenuity, as she made to lift the fifth veil and reveal her newest invention, I interrupted with a splutter. “Excuse me, Professor. I believe I may have deduced what it is you have created...”
What was the Professor's invention?
The five taken together form, not a sequence, but a complete set.