Eye of Ojer Taq // Apex Observatory

You may exile tokens you control as part of the materials required. However, because they aren't cards and won't stay in exile, any abilities that refer to what you "used to craft" the back faces won't refer to anything.

If the materials required include multiple objects, you may exile some of them from among permanents you control and the rest from among cards in your graveyard. You don't have to choose all permanents or all cards from your graveyard.

Card types that may appear in a normal game of Magic are artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery. Supertypes such as snow and basic may not be chosen. Subtypes such as Bird, Equipment, and Forest also may not be chosen. Land may be chosen, but it's not a good idea.