Cast Seasons Past by paying ({4} magic symbol) ({G} magic symbol) ({G} magic symbol) , returning Demonic Tutor, Walk the Aeons, and any number of cards with different mana costs to your hand and putting Seasons Past on the bottom of your library.
Cast Demonic Tutor by paying ({1} magic symbol) ({B} magic symbol) , putting Seasons Past from your library into your hand.
Cast Walk the Aeons by paying ({4} magic symbol) ({U} magic symbol) ({U} magic symbol) , granting you an extra turn.