The matched pair who agree on everything except who started it

Tweedledee and Tweedledum stand under a tree with their arms around each other’s shoulders, identical down to the embroidery on their collars, and explain to Alice that contrariwise, if it was so, it might be; and if it were so, it would be; but as it isn’t, it ain’t. They recite “The Walrus and the Carpenter” with great feeling, fight a brief and ceremonial battle over a broken rattle, and inform Alice — to her considerable alarm — that she is only a thing in the Red King’s dream. They are the most agreeable pair in either book, provided you don’t ask them to settle anything.