None keeps a deck in Bracket 1 or 2. One to three make it Bracket 3, and four or more make it Bracket 4.

A combo raises the deck to its own bracket. A fast two-card infinite is Bracket 4.

• Combat Celebrant + Kiki-Jiki, Mirror Breaker Bracket 4
  • 
  • 
  • ∞Infinitecombat phases
  • ∞Infinitecreature tokens with haste
  • ∞Infinitecreature ETB Infinite creature ETB
    • ETB: enters the battlefield
  Steps on Commander Spellbook
• Kiki-Jiki, Mirror Breaker + Village Bell-Ringer Bracket 4
  • 
  • 
  • ∞Infinitecreature tokens with haste
  • ∞Infinitedeath triggers
  • ∞Infinitecreature ETB Infinite creature ETB
    • ETB: enters the battlefield
  • ∞Infinitecreature LTB Infinite creature LTB
    • LTB: leaves the battlefield
  • ∞Infinitemana creatures you control can produce
  • ∞Infinitecreature sacrifice triggers
  • ∞Infiniteuntap of creatures you control
  Steps on Commander Spellbook
• Combat Celebrant + Mirage Phalanx Bracket 3
  • 
  • 
  • ∞Infinitecombat phases
  • ∞Infinitecreature tokens with haste
  • ∞Infinitecreature ETB Infinite creature ETB
    • ETB: enters the battlefield
  Steps on Commander Spellbook

Any rules out Bracket 1. Brackets 2 and 3 allow a few, never chained or looped; Icarian counts three or more as Bracket 3.

Any at all makes it Bracket 4. Brackets 1 to 3 don't allow it.