They watched intently as a strange machine was brought into the room. The two gamblers sat close to each other. A third Martian attached electrodes to their heads, then flipped a lever on the ancient, rusty machine.
The Martian who lost the game grimaced with pain.
A needle on the machine's single dial moved all the way to the right, then quickly returned to its original position.
An expression of joy spread the victor's thin lips into a wide smile.
A few seconds later, the electrodes were removed from their heads.
Tharp grunted his bafflement.
"Duchal," Farrell explained quickly, "means an expression of sorrow or pain. By means of that machine, the winner was able to receive in his brain the sensation of the loser's physical and mental agony at losing the game."
"That's what they were betting?" Tharp asked unbelievingly.
"Yes. It's the same principle as humans who play games merely for the disappointed expression on the loser's face. The Martians do it a little differently: they have a machine that transmits the loser's pain into the victor's brain. The Martians are constructed in such a way that the agony of another person, implanted in their minds, is very pleasant to them."