From "Manual of Muad'Dib" by the Princess Irulan

Double meaning . . . double meaning , the Baron thought.
He looked up at the new talismans flanking the exit to his hall—the mounted bull's head and the oil painting of the Old Duke Atreides, the late Duke Leto's father. They filled the Baron with an odd sense of foreboding, and he wondered what thoughts these talismans had inspired in the Duke Leto as they hung in the halls of Caladan and then on Arrakis—the bravura father and the head of the bull that had killed him.
"Mankind has ah only one mm-m-m science," the Count said as they picked up their parade of followers and emerged from the hall into the waiting room—a narrow space with high windows and floor of patterned white and purple tile.
"And what science is that?" the Baron asked.
"It's the um-m-m-ah-h science of ah-h-h discontent," the Count said.
The Houses Minor behind them, sheep-faced and responsive, laughed with just the right tone of appreciation, but the sound carried a note of discord as it collided with the sudden blast of motors that came to them when pages threw open the outer doors, revealing the line of ground cars, their guidon pennants whipping in a breeze.
The Baron raised his voice to surmount the sudden noise, said, "I hope you'll not be discontented with the performance of my nephew today, Count Fenring."
"I ah-h-h am filled um-m-m only with a hm-m-m sense of anticipation, yes," the Count said. "Always in the ah-h-h process verbal, one um-m-m ah-h-h must consider the ah-h-h office of origin."
The Baron hid his sudden stiffening of surprise by stumbling on the first step down from the exit. Process verbal! That was a report of a crime against the Imperium!
But the Count chuckled to make it seem a joke, and patted the Baron's arm.
All the way to the arena, though, the Baron sat back among the armored cushions of his car, casting covert glances at the Count beside him, wondering why the Emperor's errand boy had thought it necessary to make that particular kind of joke in front of the Houses Minor. It was obvious that Fenring seldom did anything he felt to be unnecessary, or used two words where one would do, or held himself to a single meaning in a single phrase.
They were seated in the golden box above the triangular arena—horns blaring, the tiers above and around them jammed with a hubbub of people and waving pennants—when the answer came to the Baron.
"My dear Baron," the Count said, leaning close to his ear, "you know, don't you, that the Emperor has not given official sanction to your choice of heir?"
The Baron felt himself to be within a sudden personal cone of silence produced by his own shock. He stared at Fenring, barely seeing the Count's lady come through the guards beyond to join the party in the golden box.
"That's really why I'm here today," the Count said. "The Emperor wishes me to report on whether you've chosen a worthy successor. There's nothing like the arena to expose the true person from beneath the mask, eh?"
"The Emperor promised me free choice of heir!" the Baron grated.
"We shall see," Fenring said, and turned away to greet his lady. She sat down, smiling at the Baron, then giving her attention to the sand floor beneath them where Feyd-Rautha was emerging in giles and tights—the black glove and the long knife in his right hand, the white glove and the short knife in his left hand.
"White for poison, black for purity," the Lady Fenring said. "A curious custom, isn't it, my love?"
"Um-m-m-m," the Count said.
The greeting cheer lifted from the family galleries, and Feyd-Rautha paused to accept it, looking up and scanning the faces—seeing his cousines and cousins, the demibrothers, the concubines and out-freyn relations. They were so many pink trumpet mouths yammering amidst a flutter of colorful clothing and banners.
It came to Feyd-Rautha then that the packed ranks of faces would look just as avidly at his blood as at that of the slave-gladiator. There was not a doubt of the outcome in this fight, of course. Here was only the form of danger without its substance—yet . . .
Feyd-Rautha held up his knives to the sun, saluted the three corners of the arena in the ancient manner. The short knife in white-gloved hand (white, the sign of poison) went first into its sheath. Then the long blade in the black-gloved hand—the pure blade that now was unpure, his secret weapon to turn this day into a purely personal victory: poison on the black blade.
The adjustment of his body shield took only a moment, and he paused to sense the skin-tightening at his forehead assuring him he was properly guarded.
This moment carried its own suspense, and Feyd-Rautha dragged it out with the sure hand of a showman, nodding to his handlers and distracters, checking their equipment with a measuring stare—gyves in place with their prickles sharp and glistening, the barbs and hooks waving with their blue streamers.
Feyd-Rautha signaled the musicians.
The slow march began, sonorous with its ancient pomp, and Feyd-Rautha led his troupe across the arena for obeisance at the foot of his uncle's box. He caught the ceremonial key as it was thrown.
The music stopped.
Into the abrupt silence, he stepped back two paces, raised the key and shouted. "I dedicate this truth to . . . " And he paused, knowing his uncle would think: The young fool's going to dedicate to Lady Fenring after all and cause a ruckus!
" . . . to my uncle and patron, the Baron Vladimir Harkonnen!" Feyd-Rautha shouted.
And he was delighted to see his uncle sigh.
The music resumed at the quick-march, and Feyd-Rautha led his men scampering back across the arena to the prudence door that admitted only those wearing the proper identification band. Feyd-Rautha prided himself that he never used the pru-door and seldom needed distracters. But it was good to know they were available this day—special plans sometimes involved special dangers.
Again, silence settled over the arena.
Feyd-Rautha turned, faced the big red door across from him through which the gladiator would emerge.
The special gladiator.
The plan Thufir Hawat had devised was admirably simple and direct, Feyd-Rautha thought. The slave would not be drugged—that was the danger. Instead, a key word had been drummed into the man's unconscious to immobilize his muscles at a critical instant. Feyd-Rautha rolled the vital word in his mind, mouthing it without sound: "Scum!" To the audience, it would appear that an un-drugged slave had been slipped into the arena to kill the na-Baron. And all the carefully arranged evidence would point to the slavemaster.
A low humming arose from the red door's servomotors as they were armed for opening.
Feyd-Rautha focused all his awareness on the door. This first moment was the critical one. The appearance of the gladiator as he emerged told the trained eye much it needed to know. All gladiators were supposed to be hyped on elacca drug to come out kill-ready in fighting stance—but you had to watch how they hefted the knife, which way they turned in defense, whether they were actually aware of the audience in the stands. The way a slave cocked his head could give the most vital clue to counter and feint.
The red door slammed open.
Out charged a tall, muscular man with shaved head and darkly pitted eyes. His skin was carrot-colored as it should be from the elacca drug, but Feyd-Rautha knew the color was paint. The slave wore green leotards and the red belt of a semishield—the belt's arrow pointing left to indicate the slave's left side was shielded. He held his knife sword-fashion, cocked slightly outward in the stance of a trained fighter. Slowly, he advanced into the arena, turning his shielded side toward Feyd-Rautha and the group at the pru-door.
"I like not the look of this one, "said one of Feyd-Rautha's barb-men. "Are you sure he's drugged, m'Lord?"
"He has the color," Feyd-Rautha said.
"Yet he stands like a fighter," said another helper.
Feyd-Rautha advanced two steps onto the sand, studied this slave.
"What has he done to his arm?" asked one of the distracters.
Feyd-Rautha's attention went to a bloody scratch on the man's left forearm, followed the arm down to the hand as it pointed to a design drawn in blood on the left hip of the green leotards—a wet shape there: the formalized outline of a hawk.
Hawk!
Feyd-Rautha looked up into the darkly pitted eyes, saw them glaring at him with uncommon alertness.