Wallace opened what appeared to be a common twelve-ounce container and poured out enough marbles to fill a five-gallon bucket. Bernard was stunned. "How did you do that?"

Wallace beamed with pride over his latest invention. "It's bigger on the inside than it is on the outside."

Bernard, for once, was genuinely impressed. "That's amazing! How does it work?"

Wallace reached for his laser pointer in his lab coat pocket and walked to the chalk board. "You know how matter and energy are essentially the same thing?"

"No, not really."

Wallace was unperturbed. "Well, they are. And one can be converted to another. It turns out that space and time are the same way. We've known since Einstein that space and time are essentially two sides of the same coin. But I've figured out that, just like matter can be converted to energy, time can be converted to space!"

"So you're converting time into space to make the can bigger on the inside than it is on the outside?"

"Exactly!"

"So where do you get the time?"

"Ah, that's the real beauty of it." Wallace pointed to some incomprehensible scribblings in the corner of the chalk board. "The time comes from inside the container. Therefore, not only is the container bigger on the inside than it is on the outside, but time passes more slowly on the inside than it does on the outside. Space-time has to be conserved, so increasing one requires a corresponding decrease in the other."

"So what can it be used for?"

Wallace was dumbfounded. "Isn't it obvious? Storage! A coin purse could hold the Queen Mary! All right, maybe that's not very practical, but how about a shoe-box sized refrigerator that holds a month's worth of groceries? And because of the diminished time flow, milk would take months to go bad instead of just days! Goods could be transported by bicycle instead of freight train! Human organs could be stored indefinitely before being transplanted! Large payloads could be launched into space with minimal effort! This will change EVERYTHING!"

Bernard was unmoved. "Can you reverse the process?"

"What do mean?"

"Can you, you know, convert space into time?"

"Well, yeah, I can. But why would you want to do that? That would make the container much smaller on the inside than it is on the outside, which is pretty unremarkable. And time would also pass more quickly on the inside. You'd essentially have a cramped space where everything grows old in record time."

"That's it! That's what I want! Make it do that!"

Wallace was completely lost. "Why on Earth would you want that?"

Bernard was already heading back to his office when he turned and added, "And make it big enough for my mother-in-law to live in!"