"By the way, Kira, why had you suddenly become interested in other worlds too?"
Mokuba accompanied Kira down a long metal corridor. This was one of KaibaCorp's cutting-edge research facilities. As they walked, he glanced at Kira curiously.
"Too?"
Kira repeated the word, then immediately understood.
"You mean President Kaiba?"
It seemed that ever since Atem had vanished, President Kaiba had developed a tremendous interest in technology for traveling to different dimensions. In just one year, he had successfully developed equipment capable of Dimensional Travel. The level of Black Technology was truly terrifying.
"Yeah. Brother has been heavily developing Different Dimension-related technology for years. I'm not particularly interested in it myself, but I've picked up some of the theories lately."
Mokuba tilted his head in thought.
"Let me see, how did they put it again? Oh, right."
Mokuba nodded to himself and said,
"Although we achieved Dimensional Travel long ago and can enter certain Spirit Dimensions, some scholars in our group have proposed that while the spirits' worlds appear to be Different Dimensions, they are actually still extensions of the reality we inhabit.
"The reality we live in, the world humans can see, is merely the tip of the iceberg. What analogy did they use again? Ah, right. Cards."
"Cards?"
"Yeah. The front and back of a card," Mokuba said. "Using a card as an analogy, the world humanity lives in is the front of the card, while the spirits' dimensions are spread across the back.
"But fundamentally, they're still the same card, the same dimension."
Kira felt like he understood now. "And so-called Parallel Worlds would be different cards entirely. Is that the idea?"
"You catch on fast."
Mokuba smiled and nodded.
"Yeah, that was more or less the idea. Then our Research Department discovered that travel between different