If youre unfamiliar with this interaction, Grindstone mills your opponent for two cards, and if those cards share a color, you repeat the process
That leads me to a specific anecdote, which is that the only instance of what could be called grinding I had to do in the game involved fighting some guy in a lab to get Water Energy cards in order to build a specific setup
Let's break down what makes Zinnia so incredible as an out-of-the-box, precon Commander
Mana Vault (Kaladesh Inventions Series) The Kaladesh series returns once again, and Mana Vault is a valuable treasure indeed
Disney says its important to rotate the card sets to keep competition fresh and change the meta from time to time
It's arguably one of the best cards for Type Four from the set (Rules are - infinite mana but just one spell per turn so counters are good there since they cannot be overwhelmed by casting more spells than you have mana, and a five cost counter is first turn able there)