Activate Bartolomé del Presidio by sacrificing Boonweaver Giant.
When Boonweaver Giant dies, Mortuary and Pattern of Rebirth trigger.
Resolve the Mortuary trigger, putting Boonweaver Giant on the bottom of your library from your graveyard.
Resolve the Pattern of Rebirth trigger, putting Boonweaver Giant from your library onto the battlefield.
When Boonweaver Giant enters the battlefield, it triggers, returning Pattern of Rebirth from your graveyard to the battlefield attached to Boonweaver Giant.
Resolve the Bartolomé del Presidio ability from step 1, putting a +1/+1 counter on it.
Repeat.
Results
Infinite +1/+1 counters on Bartolomé del Presidio.