Based on Hikaru's "Reverse on Sarah" - up to a point! The third paragraph is fixed.)
"I was going to try Sarah," explained Jon.
"Do that and you get two bitches," replied Karyn. "Or one less bitchy and one more bitchy. And Sarah's bad enough."
"I don't think it has to work that way," explained Jon. "Yes, the device might do a reverse average - one more bitchy and one less bitchy. Or it might do a reverse pick one - one is bitchy and the other can be anything at all. And there's only one way to find out."
Jon aimed the device at Sarah and pressed 'Enter'. Light engulfed Sarah's body as she seemed to stretch out and twist, her body elongating and then, like a drop of water falling from a faucet, suddenly separating. A moment later there were two girls there. They were sitting next to each other--the empty seat near Sarah was now occupied. The device, which showed the name of its target, now had two names on it. "Sarah Smith" and "Melissa McMillan." Both were still age 17.
Karyn gasped. "I think I saw somebody vanish." She pointed at a seat at the other end of the classroom from Sarah and Melissa.
"But I didn't aim there," protested Jon. "Besides, this device can't make anybody disappear. It creates more people."
"Or does it?" asked Karyn. "What if ..."
Jon looked at the readout on the device. "Smith. Melissa. Melissa Smith! She's where all the other traits came from!"
Karyn and Jon studied the two new girls. Their appearance confirmed Jon's hypothesis.
Sarah Smith had hair that was long like Sarah McMillan's but red like Melissa Smith's. Melissa McMillan's hair was in a pony tail like Melissa Smith's but blonde like Sarah McMillan's. Sarah Smith was covered in freckles like Melissa Smith, but Melissa McMillan was freckle-free. They had traded coloration. Red hair and freckles came together as a package. Their faces were mixtures of the old Sarah and Melissa. Their clothing was also mixed up. Styles and colors had been scrambled. The old Sarah's pink dress had turned into the new Sarah's pink T-shirt and a denim skirt. The old Melissa's jeans were now the new Melissa's pink pants, and her white T-shirt turned into a blouse resembling the top half of Sarah's dress.
"Oh God, what have I done?" asked Jon.
"I never cared much for Melissa ... the old Melissa ... anyway," stated Karyn.
"Neither did I, but ... what'll happen the next time?" Jon was trembling. "You or I might be scrambled with the target, even if we're not next to that person! Why Melissa? I wish I knew!"
Jon blinked. He did know. "It can't really create a new person out of nothing. The total number of people has to remain the same, no matter what. So if someone is split, the traits of that person are combined with the traits of the most convenient person, resulting in two amalgams. 'Most convenient' doesn't necessarily mean adjacent. A non-targeted person is chosen whose parents had an opportunity to mate with the parents of the targeted person. The mothers of the old Sarah and Melissa met their future husbands back in high school during a double date. In this new reality, they still double dated, though the pairings were different. Sarah Smith is the daughter of the old Melissa's dad and the old Sarah's mom. And Melissa McMillan is the daughter of the old Sarah's dad and the old Melissa's mom."
"What about their siblings, if any?" asked Karyn.
"I wish we knew," said Jon.
Karyn blinked along with him. The same information popped into their heads: siblings were also scrambled unless the original parents could somehow get together before and/or after the birth of the transformees. So if Jon got scrambled with somebody else, Zoe and Mikey might still be genetically identical if Jon's parents could "reunite" after the birth of the Jon/other mixture.
"Uh oh," said Karyn. "I think you should've specified who 'we' were."
Everyone in class looked dazed. Now they all knew.
