"It can — and just the same thought crossed my mind. The Indestructible thinks that we are running a communications check and tells me that it can accept up to seven hundred signals a second for repeat and verification. Our computer will read the returned signal and send an affirmative answer to each one. But of course all the signals will be going through the discrimination circuits, and if the correct signal is sent, the mothball defenses will be turned off."
"That seems like an obvious trick that would not fool a five-year-old," Kerk said.
"Never overestimate the intelligence of a computer. You forget that it is a machine with zero imagination. Now, let me see if this will do us any good." He punched keys rapidly, then muttered a curse and kicked the console. "No good. We will have to run nine to the tenth power numbers and, at seven hundred a second, it will take us about five months to do them all."
"And we have just three weeks left."
"I can still read a calendar, thank you, Meta. But we'll have to try in any case. Send alternate numbers from one up and counting from 9,999,999,999 back down. Then we'll get the navy code department to give us all their signals to send as well; one of them might fit. The odds are still about five to one against hitting the right combination, but that is better than no odds at all. And we'll keep working to see what else we can think of."
The navy sent over a small man named Shrenkly, who brought a large case of records. He was head of the code department, and a cipher and puzzle enthusiast as well. This was the greatest challenge of his long and undistinguished career. He hurled himself into the work with growing enthusiasm.
"Wonderful opportunity, wonderful. The ascending and descending series are going out steadily. In the meantime I am taping permutations and substitutions of signals which will—"
"That's fine, keep at it," Jason said, smiling enthusiastically and patting the man on the back. "I'll get a report from you later, but right now we have a meeting to attend. Kerk, Meta, time to go."
"What meeting?" Meta asked as he tried to get her through the door.
"The meeting I just made up to get away from that monomaniacal enthusiast," he said when he finally got her into the corridor. "Let him do his job while we see if we can find another way in."
"I think what he has to say is very interesting."
"Fine, you talk to him — but not while I am around. Let us now spur our brains into action and see what we can come up with."
What they came up with was a number of ideas of varying quality but uniform record of failure. There was the miniature-flying-robot fiasco, where smaller and smaller robots were sent and blasted out of existence, right down to the smallest, about the size of a small coin. Obsessed by miniaturization, they constructed a flying-eye apparatus no larger than the head of a pin. It dragged a threadlike control wire after it that also supplied current for the infinitesimal ion drive. This device sparked and sizzled its way to within fifteen kilometers of the Indestructible before the sensors detected it and neatly blasted it out of existence with a single shot.
There were other suggestions and brilliant plans, but none of them worked out in practice. The great ship floated serenely in space, reading seven hundred numbers a second and, in its spare time, blowing into fine dust any object that approached it. Each attempt took time; the days drifted by steadily. Jason was beginning to have a chronic headache and had difficulty sleeping. The problem seemed insoluble. He was feeding figures about destruction distances into the computer when Meta looked in on him.
"I'll be with Shrenkly if you need me," she said.
"Wonderful news."
"He taught me about frequency tables yesterday, and today he is going to start me on simple substitution ciphers."
"How thrilling."
"Well, it is to me. I've never done anything like this before. And it has some value: we are sending signals and one of them could be the correct one. It certainly is accomplishing more than you are with all your flying rocks. And there are only two days to go, too."
She stalked out and slammed the door. Jason slumped with fatigue, aware that failure was hovering close. He was pouring himself a huge glass of Old Fatigue Killer when Kerk came in.
"Two days to go," Kerk said.
"Thanks. I wouldn't have known if you hadn't told me. I am well aware that a Pyrran never gives up, but I am getting the sneaking suspicion that we are licked."
"We are not beaten yet. We can fight."
"A very Pyrran answer — but it won't work this time. We just can't barge in there in battle armor and shoot the place up."
"Why not? Small-arms fire would just bounce off of us — as well as the low-powered rays. All we have to do is dodge the big stuff and bull through."
"That's all! Do you have any idea how we are going to arrange that?"
"No. But you will figure something out. And you better hurry."
