Requires

Codie, Vociferous Codex must be on the battlefield. Vigean Graftmage must be on the battlefield. Training Grounds must be on the battlefield. Mana needed:

Steps

1. Activate Codie by paying and tapping it, adding .
2. Activate Vigean Graftmage by paying , untapping Codie.
3. Repeat.
4. Once you have an arbitrarily large number of Codie triggers, you may cast any instant or sorcery spell by paying its mana cost.
5. Codie triggers for each time you activated its ability.
6. 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.
7. Repeat step 6 for each remaining trigger.
8. You may also repeat this combo for each instant and/or sorcery card in your hand, and on subsequent turns.

Results