Babylon: When you have the second stage of the wonder that allows you to buy your last 2 cards in the age instead of discarding, does this count as 1 turn or as 2 separate turns? Here's why I ask... I needed to buy glass from my neighbor. Each card needed me to buy a glass, and he only had 1 glass. If the cards count as 1 turn, I could only buy 1, and would have to discard the other card to collect 3 coins. If the cards were 2 turns, then I would buy the glass twice in 2 separate transactions. After 15 minutes debate, our group voted that it was 2 turns. But we would like to know what other people think.
The designer, Antoine Bauza, has responded to this question on BGG, it is as if the Babylon player had two turns. You get to produce resources twice, buy twice from your neighbor, and even receive production from your newly built/discarded 6th card.
Q: When playing both cards in round 6 to build two buildings: Can you use one resource twice for each of the buildings?
A: Yes, it's two different cards, like two different turns... The first could help you to play the second (discard the 6th for money and use the money to play the 7th for example...)
This can also be somewhat surmised from the rules, since you need to have that stage of the wonder built to "use it." (page 9)
Clarification: - during the sixth turn, the player can therefore play both cards they have in hand. If the second stage of the Wonder is not built, the Babylon player can then build it on their sixth turn and then play the seventh card instead of discarding it.