O2 8/18
Chapter Seven:
When Don's shift ended he went straight to see Charlie and found the young mathematician in the midst of a full blown P vs. NP style obsession. The living room and dining room both were buried under loose sheets of paper, strewn with open binders and notebooks, littered with heavy text books and nearly unrecognizable with white poster paper covering almost every wall, all covered in Charlie's distinctive handwriting.
"Don, there's nothing here. This sequence... It's meaningless. I've cross-referenced it across the board and it doesn't match anything. Sure, it could be a computer password but then anything could. Why would O give us this clue unless she thought it would be something we could figure out and use?"
Charlie was pacing up and down, trampling papers with each step.
Don knew he had to get his agitated brother to calm down so he stood in his path and held him by the upper arms to still his progress. Charlie twisted out of his brother's grasp and kept moving. Don grabbed his lower arm as he passed, giving it a squeeze to let Charlie know he should pay attention to him. Charlie froze; his thought processes instantly envisioning a possible solution to the problem that had been plaguing them all day.
"Don!" Charlie said, with wonder in his voice. "I think you might have misunderstood the message."
"What makes you say that?"
Charlie pulled his brother down to sit on the couch with him. Charlie offered Don his arm. "Here, pretend I'm you and you're O. Use my arm and show me exactly how she tapped out the message to you."
Don referred back to his notes just to be certain, then performed the same sequence of grasps and taps that Olivia had done to his arm. He only had to do it once and Charlie leapt up and scribbled something on a sheet of paper.
"There's an obscure branch of math that's rather archaic called Fingermath, and one version is called Chisanbop," Charlie explained hurriedly. "While Olivia and I would know about this method of using fingers as a kind of portable abacus the general populace wouldn't. However, Olivia could adapt that method to something any person might understand. I just failed to recognize that she'd adapted it because you never told me exactly how she communicated it to you."
"Charlie, what are you getting at?" Don knew this information was crucial and he needed answers.
"She didn't intend to communicate any fives in the sequence, Don. She only had one hand to work with..."
In a flash, Don understood completely. "So she used math to tell me when she had a number over five by grasping first."
"That's right, so a grasp using all five fingers literally meant five plus or more precisely take five and hold it until I give you the number to add to it."
Charlie handed him the slip of paper and Don read it quickly.
4 C 1 1 5 2 5 3 5 4 4 C11 52 53 54 4 C11 789 4 CII 789
"It's a license plate number," Charlie explained. "The probability is over 90 percent that while she tapped out two number ones what she really saw was the letter I twice since standard plates in California are one number, three letters, then three numbers."
"Doesn't matter, we'll run them both." Don already had his cell phone out and was dialing Kim's number.
"I have two possible license plate numbers for you. They're from Olivia Brecht."