Echoes of Eternity and Cloud Key on the battlefield (Cloud Key with "Artifact" chosen).
Steps
Cast Sensei's Divining Top by paying ({0} magic symbol) .
Echoes of Eternity triggers, creating a copying the Sensei's Divining Top spell.
Resolve both Sensei's Divining Top spells.
Activate the nontoken Sensei's Divining Top by tapping it, causing you to draw a card and put Sensei's Divining Top from the battlefield onto the top of your library.
Activate the token Sensei's Divining Top by tapping it, causing you to draw Sensei's Divining Top, and causing you to put the token Sensei's Divining Top from the battlefield onto the top of your library.