Saheeli Engineer of Power

+1: You may tap X artifacts you control, if you do create X 1/1 colourless servo creature tokens.
0: Create a colourless Powerstone artifact with "tap this artifact add 1 colourless mana to your mana pool.
-2: Until the end of turn, whenever you tap any artifact for mana, add an additional 1 mana to your mana pool.