Phyrexian Arena looks like it will be the business, but its no match for blue's best enchantment, Rhystic Study
Orzhov Blink (6.2% of the Winner's Metagame) 4 Overlord of the Balemurk 4 Phelia, Exuberant Shepherd 4 Solitude 4 Witch Enchanter 4 Marsh Flats 4 Thoughtseize 4 Ketramose, the New Dawn 3 Emperor of Bones 3 Ephemerate 3 Fatal Push 3 Godless Shrine 3 Flickerwisp 3 Relic of Progenitus 2 Plains 2 Shadowy Backstreet 2 Bleachbone Verge 2 Prismatic Ending 2 Windswept Heath 1 Boggart Trawler 1 Swamp 1 Sacred Foundry 1 Arid Mesa 4 White Orchid Phantom 3 Wrath of the Skies 2 Drannith Magistrate 2 Vindicate 2 Aven Interrupter 1 Elesh Norn, Mother of Machines 1 Orcish Bowmasters Orzhov Blink thrives on the potent synergy between Overlord of the Balemurk and Phelia, Exuberant Shepherd
Final Thoughts So yes, an artifact is a spell in MTG, but only during the casting window
Yes, that is right
With that, there arn't that many dead draws if you have the 4 mana to cast Bonehoard without having sacrified treasures, so the nonbos are quite limited
Beyond this, there are various other categories of varying complexity, and even problems for which there are no algorithms to solve them
