*
Note: This story is a game of skill. Can you help Thad and Elizabeth solve it?
*

"Which door should we open? Help me think."

"I have no idea..." Thad let himself sag against the wall. Even with the support, he could feel himself trembling with fatigue and fear.

"Which one?" she murmured, studying the doors; back turned toward him, hands on hips. "Hell," she said, "there's a clue here somewhere. I'm positive. There has to be."

"Elizabeth," he began. "What..." His voice came out rasping and thin. It shocked him.

"This clue," he said, groping for steadiness. "Explain this, please. What exactly are you looking for? How will you know it when you see it?"

"It's obvious, I'd think," she said. Turning to face him, she seemed to loom, then suddenly recede. Expect disoriention, he thought, you're dehydrated.

"We've been kidnapped by parties unknown -- my vote's still for aliens, by the way. Held, then dropped into this... labyrinth, or whatever it is. Inched our way through. Tackled games of skill, of wit... and learned that, incidentally, our captors aren't above penalizing us for a wrong guess -- "

"Exploding thresholds," he muttered. "Weight-dropped arches, and that napalm thing --"

"Horrid stuff, yes. It's clear they'd let us die here, and want us to know it. ...That brings us to these doors."

"Exactly." Which stood before them now in a neat row. Heavy, simple, solid. Identical, except for their color. The smooth surface of the first shone with a green luster; the second, white; the third, a warm gold.

Eyes throbbing, head pounding; dehydration and low blood sugar were taking him down. "Why don't you just pick one?" he said, feeling despair wash through him. "Hand on knob, shove it open. It'll blow us up or it won't. That's better than waiting here to starve to death!"

Elizabeth scowled. "With due respect, Thad, no. Help me think this through instead. I can find the clue --"

"There is no clue, Elizabeth!"

"Everything can be understood if you look closely. We can find the key. Help me think! It's here if we look hard enough... They can manipulate everything in our environment, Thad. Examine everything. Where would an alien put the pattern? How would they hide the key?"

It's here somewhere. Think like an alien. Everything can be understood....

White, green, gold. How would a master manipulator hide the clue?...

Impossible. Thad closed his eyes. Elizabeth stood, silent, still staring at the doors.

~
Which is the right door? If you can find it, post your answer in the comments. But don't explain how you solved the puzzle: let others test their wits.