You have a basic Mountain, Forest or Swamp in library.
Steps
1Play Riveteers Overlook.
2Riveteers Overlook enters the battlefield, triggering itself and Stone-Seeder Hierophant.
3Resolve the Stone-Seeder Hierophant trigger, untapping it.
4Activate Stone-Seeder Hierophant by tapping it, untapping any land you control.
5Resolve the Riveteers Overlook trigger, causing you to sacrifice it, then search your library for a basic Forest, Swamp or Mountain card, put it onto the battlefield tapped, and gain 1 life.
6The basic land enters the battlefield, triggering Stone-Seeder Hierophant, untapping Stone-Seeder Hierophant.
7Activate Stone-Seeder Hierophant by tapping it, untapping Scaretiller.
8Activate Scaretiller by tapping it, adding .
9Scaretiller triggers, returning Riveteers Overlook from your graveyard to the battlefield tapped.