"Burlesque it," Sean said. "Do it in slow motion." He demonstrated. "Like this. Ha—ha—ha—ha."
"Got it!" Mike exclaimed. "It's not a single sound. It's a series of them. It's the old story of the soldiers crossing the bridge. It's not each individual soldier; it's the cadence. Not ha, but ha—ha—ha."
"Like kicking at the lock of a door instead of pushing on it steadily to get it open; like chipping at a rock instead of trying to smash it with one blow—there's a slough of analogies if we wanted to go on with it."
"That one Krak muttered something about his ears," Mike put in.
Sean nodded. "That, I think, marks the spot of their Achilles heel. They're like us in many ways—but one difference apparently lies in their ears. I'll get old Doc Perkins to dissect some of them.
"My own idea is that their balance canals are constituted differently somehow than ours. Those two Kraks gave all the appearance of being unable to maintain their balance. In us, those ear canals are gyroscopes. That's why even blind persons are aware when they begin to deviate from an upright position.
"Both our canals of balance and those of the Kraks probably function the same way, but the extra gravity of this planet may have wrought the chink which we found. With study and experimentation we should find out for sure just what happens." Sean stopped talking, gazed at the people around him who were laughing.
He felt his chest swelling with pride. Man was on the road back—back to Earth with its rolling green hills, its blue skies, its brown mountains, its myriad sounds and smells and sights. Man was going home with a weapon to cast out the invader.
He stood for a long time, Mike's hand on his arm, watching these happy humans. Even the black and red of Karrar was softened by the joyous light in their clear unfilmed eyes.
Finally, Sean McKenna said,