Codie, Vociferous Codex | Chain Stasis | Training Grounds

Cards

Cast
Chain Stasis by paying ({U} magic symbol) , targeting
Codie.
Holding priority, activate
Codie by paying ({2} magic symbol) and tapping it, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Resolve
Chain Stasis, untapping
Codie and causing you to pay ({2} magic symbol) ({U} magic symbol) to copy
Chain Stasis, with the copy targeting
Codie.
Repeat from step 2.
Once you have an arbitrarily large number of
Codie triggers, you may choose not to copy
Chain Stasis and cast any instant or sorcery by paying its mana cost, reduced by the ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) added in step 1.
Codie triggers for each time you activated its ability.
Resolve the first trigger, causing you to exile cards from the top of your library until you exile an instant or sorcery spell with lesser mana value, and allowing you to cast that spell without paying its mana cost.
Repeat step 6 for each remaining trigger.
You may also repeat this combo for each instant and sorcery card in your hand as mana permits, and on subsequent turns.

Cast all instants and sorceries in your library with mana value less than spells you cast.
Infinite magecraft triggers.