Saheeli, the Sun's Brilliance, Mana Echoes, Sky Hussar, and Gemstone Array

Prerequisites

• Saheeli, the Sun's Brilliance on the battlefield
• Mana Echoes on the battlefield
• Sky Hussar on the battlefield
• Gemstone Array on the battlefield
• Saheeli does not have summoning sickness
• available, plus an additional if you control less than three creatures that share a creature type with Sky Hussar

Steps

1. Activate Saheeli by paying and tapping it, creating a token copy of Sky Hussar with haste
2. When the token Sky Hussar enters the battlefield, it and Mana Echoes trigger
3. Resolve the Sky Hussar trigger, untapping all creatures you control
4. Holding priority, if you control less than four creatures that share a creature type with Sky Hussar, repeat steps 1 through 3 one additional time
5. Resolve all Mana Echoes triggers, adding for each creature you control that shares a creature type with Sky Hussar for each trigger resolved this way
6. Activate Gemstone Array's first ability twice by paying , putting two charge counters on it
7. Activate Gemstone Array's second ability twice by removing two charge counters from it, adding
8. Repeat

Results

• Infinite ETB
• Infinite colored mana
• Infinite colorless mana
• Infinite creature tokens with haste
• Infinite untap of creatures you control