MTG Salvation

From the first book I saw, Fowler's UML Distilled:

"Communication diagrams, a kind of interaction diagram, emphasize the data links between the various participants in the interaction."

(Yes, I know... but I was studying for a mid-term before bed last night.)

Forced Perspective 2WUR
Enchantment (R)
Whenever a player casts a spell that has multiple targets, any other player may pay x, where X is the converted mana cost of that spell and choose new targets for that spell.
Whenever a creature is blocked, any player may discard a card to remove the blocking creature from combat. The attacking creature is now unblocked.

*Not sure about the "unblocked" wording. Might try to clean it up before judging.*

This

Sphere of Besiegement 3
Artifact
Whenever an opponent draws a card, put a siege counter on ~.
t, Remove two siege counters from ~: Destroy target fortification or aura enchanting a land.
t, Remove four siege counters from ~: Destroy target land.
"She's got the whole world in her hands."