Activate Sensei's Divining Top's second ability by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library from the battlefield.
Cast Sensei's Divining Top from the top of your library by paying ({0} magic symbol) .
Elsha of the Infinite's prowess ability triggers, giving itself +1/+1 until end of turn.
Repeat from step 3.
Results
Infinite card draw.
Infinite draw triggers.
Near-infinitely large Elsha of the Infinite until end of turn.