Preston, Ingenious Architect

{3}{t}: Create an token artifact named Preston's
Tower with "{t}: Add one mana of any color. Use
this mana only to cast artifacts."
{5}{t}: You may cast an artifact spell from your
hand with converted mana cost less than or equal
to the number of Preston's Tower's you control without paying it's mana cost until end of turn. Activate this ability only as a sorcery.