The video at the bottom of this post shows a tactical puzzle that can arise after some common ideas are played in the Italian Game, Giuco Piano variation.
If you’d like to try to solve the puzzle before watching the solution, check out the image below. Black is going for the “center fork trick,” but it backfires due to his underdevelopment. It might look like Black is doing well–after all, he only has one minor piece left to develop–but this is the deciding factor. Can you find the win for White?