Prague is a city made for walking, and anyone who’s ever trekked through its narrow and ancient streets can’t help but be struck by the ads for the Black Theatre that are everywhere. It is one of the great Prague traditions and involves the use of black curtains, a darkened stage, and black lighting paired with fluorescent costumes in order to create intricate visual illusions. Back in November, Ireland’s footballers conjured up the grandest of illusions. Or that’s the way it seemed, anyway. A 2-0 home win against mighty Portugal to be followed by an escape to victory in Budapest…