MAGIC: THE GATHERING
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pay for .)
Search your library for an artifact card with converted mana cost X or less, put it onto the battlefield, then shuffle your library.
Whir of Invention is used in artifact-based prison decks in Modern. Whether you need Ensnaring Bridge to prevent creatures from attacking or Witchbane Orb to give yourself hexproof, Whir helps you tutor up just the right spell for the occasion.