Activate Perilous Forays by paying ({1} magic symbol) and sacrificing another creature, searching your library for a land with a basic land type and put it onto the battlefield tapped.
When the land enters the battlefield, Tiller Engine and Retreat to Emeria trigger.
Resolve the Tiller Engine trigger, untapping the land.
Resolve the Retreat to Emeria trigger, creating a 1/1 Kor Ally creature token.
Activate the land by tapping it, adding ({1} magic symbol) .
Repeat.
Results
Put all lands with a basic land type from your library onto the battlefield tapped.