From New Scientist #1099, 20th April 1978 [link]
We live, we three, on the Imperfect Isle,
Where all is not just what it ought to be.
One is a Wotta-Woppa and he never
Tells what is true, in fact a liar he.
And then there is another one who cannot
Make up his mind. Oh, shall I tell a lie?
He is a Shilli-Shalla, and makes statements,
One true, one false. But which? The constant cry.
The third one is a Pukka and we find
Nothing but truth comes from the third man’s mind.
Single figures all our dwellings,
And each one is different.
Three statements each, so read with care
And use your loaf to find what’s meant.
(1) First let me say no Shilli-Shalla I,
But I’m afraid I cannot tell you why!
(2) Then I point out that where numbers are concerned
The lower the truer; that’s the fact for which you yearned.
(3) Thirdly, no tricks,
My number’s less than six.
(1) and (2) A Pukka, I, and live at number one.
That’s two statements in a single line.
(3) Perfect, you might say, but not as perfect as C‘s square.
(1) A and B live on either side of me.
(2) Who is the Wotta-Woppa? Why it’s B.
(3) And now our verse
Has done its worst.
Just to finish with a wink,
To get this right you’ll have to think.
And with a nod,
A‘s number is not odd.
Where do A, B and C live and what are their tribes?