Requires

Saheeli, the Sun's Brilliance must be on the battlefield. Mana Echoes must be on the battlefield. Chromatic Orrery must be on the battlefield. Zealous Conscripts must be on the battlefield. Mana needed:

Steps

1. Activate Saheeli by paying and tapping it, creating a token copy of Zealous Conscripts with haste.
2. When the token Zealous Conscripts enters the battlefield, it and Mana Echoes trigger.
3. Resolve the Zealous Conscripts trigger, untapping Saheeli.
4. Resolve the Mana Echoes trigger, adding for each creature you control that shares a creature type with Zealous Conscripts.
5. Repeat.

Results