mtg march of the machine cards Set Booster [30] – The Guardtower Traditional Foil of any rarity replaces a Common in 33% of boosters. A First Look at March

2.1 Green-Dot Test Within the green dot on the back of the card, you can find a yellow spot

Then in 2017 one more ruling was added to address replacement effects: "Replacement effects that modify creatures of a certain type as they enter the battlefield will apply (or not apply) after you apply this effect

with cards like Deserted Temple and Rings of Brighthearth in combination with the aforementioned outlets can reduce the startup cost in your recipe for infinite mana, albeit quite unnecessary most of the time

For myself, I kind of a wayside fan at this point, where I play one of the games every now and then and follow news, but I'm not as hyped at every announcement