Oversized Telescope

When Oversized Telescope enters the battlefield
there must gap at least as big as the width of a standard MTG card. If this is not possible either
sacrifice Oversized Telescope or the cards encroaching on Oversized Telescope.
{t}:You may look at the top {x} cards of target opponents library and may cast one if cards as
long as its mana cost is the exact same as {x}.