{Riddle of Lightning}+ {Sensei's Divining Top} with any {Draco} or similar casting cost in hand.
How does this work if {Draco} is in the hand?
This does literally nothing
lol. thats why this kinda stuff should be in synergies and not in combos.
Oops. Thought the top was like {Brainstorm}
Then {Riddle of Lightning} + {Brainstorm} + high CMC in hand. Draw three, but the high CMC and whatever else back, scry three, put high CMC on top and bang.
This is a synergy
I actually built a deck around this, very hit and miss.