During your draw step, Archmage Ascension allows you to search your library for Nexus of Fate, reveal it and put it into your hand.
Cast Nexus of Fate by paying {5}{U}{U}, causing you to take an extra turn after this one and shuffle Nexus of Fate into your library.
Repeat each turn.

Infinite turns

Lock

Archmage Ascension

Nexus of Fate

During your draw step, Archmage Ascension allows you to search your library for Beacon of Tomorrows, reveal it and put it into your hand.
Cast Beacon of Tomorrows by paying {6}{U}{U}, causing you to take an extra turn after this one and shuffle Beacon of Tomorrows into your library.
Repeat each turn.

Combos with "Archmage Ascension"