S. O. S.
(save our stones)

Recently, my arch-nemesis the demented, old Rzeznik, stole six valuable stones from my possession. In his usual, maniacal fashion he has devised an elaborate labryrinth of puzzles, riddles, and conundrums for me to unravel in order to retrieve what is rightfully mine to begin with. Alas, I am a busy man and have no time for such diversions. Hence, I am looking for some Knights of Reason to champion my cause.
In order to prove yourself worthy of the quest I propose,
you must contribute $10 to the GRUFF fund (you Get Rzeznik Fund fund)
and answer this Most Ancient eNigma:

What walks on four legs in the morning,
Two legs at noon,
And three by evening?

Of course there are rules to be understood and rewards to be had, but we have no time for delay. Please proceed post-haste to the commencement of your journey through the warped and convoluted recesses of his mind by clicking the magic seal, which he placed on his challenge.

You have one advantage you must remember:
that old Rzeznik can almost never realize other chemists know stuff!