You have not cast an instant or sorcery this turn.
({4} magic symbol) ({U} magic symbol) ({U} magic symbol) on each odd-numbered turn, with at most ({3} magic symbol) ({U} magic symbol) available each even-numbered turn available.
Steps
Cast
Walk the Aeons by paying ({4} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Chandra triggers, copying
Walk the Aeons.
Resolve both
Walk the Aeonss, causing you to take two extra turns after this one.
Move to your next turn.
Cast etiher
Mystic Retrieval or
Call to Mind by paying its mana cost, targeting either
Call to Mind or
Mystic Retrieval in your graveyard.
Chandra triggers, copying
Call to Mind or
Mystic Retrieval, targeting
Walk the Aeons.
Resolve both
Call to Minds or
Mystic Retrievals, returning
Walk the Aeons and either
Call to Mind or
Mystic Retrieval from your graveyard to your hand.