After Black joined the team, things got pretty busy at the lab, and much more easy-going. The successful test of the quantum nano-virus opened up all sorts of avenues for research and development.

Red introduced the entanglement protocol into the formula for their memory fabric bodysuits, so that the suits could be separated along with them without having to destroy a perfectly good suit every time. Blue worked on developing a cutting mechanism that combined precision with comfort, settling on a monofilament serrated wire that oscillated ultrasonically between two tension points, like a cross between a cheese slicer and an electric carving knife. It was easily portable, and it also gave a pleasant tingling sensation on the subject.

Green spent most of her time getting a few things off her chest with Black after the initial test, but eventually, the others told her that maybe enough was enough and she should put Black back together again. At the very least, they needed to make sure that the nano-virus would allow separated parts to reattach like it was supposed to. When Green finally relented and reassembled Black, the cut surfaces joined together just like new. It took some work to get the alignment right, but once each entangled cell met with its counterpart, the quantum bridge collapsed and reestablished the physical connection, allowing the nearby cells to join more easily. Black's bodysuit was still in multiple pieces, since she'd been fitted for it while separated, but the seams joined together and disappeared once Red introduced the new formula into it.

Yellow, Orange, and Violet were hard at work on their own projects, too, but they were being far more secretive about it. All Violet would say was that she was working on a new protocol for the Banach-Tarski device, but she didn't want to say what for until she had something to show. Yellow and Orange were mostly planning and hypothesizing, until they got everyone together for an announcement.

"Okay, everyone," said Yellow. "I think it's time we took our entanglement experiments to the next level. You want to start, Orange, or should I?"

"I think you should go first," said Orange. "My presentation will take a little while to set up. I will need to borrow Red for a sec, though."

"What's that?" said Red. "What do you need?"

"Well, if I said I needed you to lend me a hand, you'd probably all boo me," said Orange. She held up Blue's slicing rig. "But I really do need to borrow your arm."

"As long as you don't distract me from Yellow, then I guess I don't mind," said Red. She raised her arm, and Orange sliced it off above the shoulder.

"Thanks, Red," said Orange. "I'll bring it right back. Yellow, over to you."

"Okay," said Yellow, as everyone else gathered around and Red sat attentively on a stool with one bare shoulder. "We've proved that the quantum nano-virus works exactly as intended, and we can use it to detach living body parts and reattach them exactly as they were."

"Evidently, yes," said Red, rubbing the spot where her arm had been for emphasis.

"And we know that the parts remain under the control of their owner while detached," said Yellow. "What Orange and I wanted to find out was this: what if we combined that functionality with the B-T device?"

"How do you mean?" said Violet. "Have you been looking over my shoulder?"

"We haven't, I promise," said Yellow. "Why? Do you want to share something with us?"

"No, no," said Violet. "It's your show."

"What we wanted to try was -"

"Sorry, sorry," said Orange. She walked back to the group carrying Red's arm. "Here you go, Red. All yours." She stuck the arm back where it belonged, and then she held up the slicer again. "Now I need the other one."

"Fine, fine," said Red. "I hope you're building up to something good."

"You'll see," said Orange, slicing through the other shoulder and walking away. "Carry on."

"As I was saying," said Yellow, "what we wanted to try was separating a limb and then duplicating it, to see if one person could control multiple copies of the same body part at once. Would they move in unison? Could they be made to move independently?"

"Would they develop their own personalities and start moving on their own?" said Green.

"I really hope not," said Yellow. "I can't even imagine how many unfortunate implications that would bring. We'll have to cross that bridge when we come to it. Who wants to step up?"

They all looked around the room. Orange walked back to the group and replaced Red's other arm.

"There we are, all done," said Orange. "We can just leave that running for a while. Where were we? Any takers?"

Black looked around the room, and then she raised her hand. "What the hey. I don't mind being adventurous."

"We have our brave volunteer!" said Yellow. "Grab a stool and lift up your arms."

"Better you than me," said Blue. "I spent enough time testing the slicer that I worried I might be hogging it."

"You been having fun chopping yourself up, Blue?" said Red.

"Later," said Blue. "I want to see what they've got in store for Black first."

"Okay, Black," said Orange. "You'll want to hook your ankles around the legs of the stool so you don't fall off. We want to take this slow." She stood in front of Black with the slicer while Yellow stood behind her and grabbed Black by the armpits. While Yellow lifted gently to support Black's weight, Orange made a slow, level slice through Black's chest, just below her breastbone. When the vibrating wire was all the way through, Yellow lifted Black's torso away, leaving her legs wrapped around the legs of the stool.

"Hey, Yellow," said Green. "Let me take that off your hands, why don't you?"

"Sure, Green," said Yellow. "All yours." She tossed Black at her, making Black give a little yelp of surprise as she flailed for Green. Green caught her and pulled her in, wrapping her arms around Black nice and snug.

"Why am I not surprised?" said Red. "And I thought Yellow and Orange were frisky."

"Hey, we're still frisky!" said Orange, setting down the slicer and pinching Yellow's butt.

"Whoa, now," said Yellow. "Science first."

Orange gave Yellow a wink, and the two of them lifted the stool with Black's lower half toward the intake door on the B-T device. Yellow closed the door and started the procedure, and the machine hummed and clicked for a few moments before the sequence ended. The device gave a few beeps to show that it was done, and then the two output doors swung open, revealing two identical stools with two identical black-clad lower halves perched on them.

"Huh," said Black. "You know, as much time as I've spent surrounded by identical duplicates, that still looks pretty weird."

"Well, whatever you do, don't make any large movements," said Yellow. "Not until we're ready to gather data. Do you have feeling in both of them? Try wiggling your toes."

"Yep," said Black. "I think I have sensation, but it's hard to tell if it's in both copies."

Yellow watched as both pairs of legs flexed their right feet up and down. "Looks like it is," said Yellow. "The motor impulses seem to be copying into both versions. Well, make sure you keep a firm grip."

Yellow and Orange lifted one stool out of the device, and then the other. Now Black was starting to feel some weird stuff. She could feel the sensation of being lifted in her gut, and at the same time, she felt like she was sitting still.

"Oh, that's weird," she said. "I'm starting to feel the difference in sensation now."

"Good," said Yellow. "We can work on that. It should be possible to retrain your brain to recognize multiple sets of sensation and action, and I want to see how long it takes."

"You don't need me for this, do you?" said Orange.

"No, I can take it from here," said Yellow. "Go ahead and see how your project is coming out."

Orange stepped around the corner where she had taken Red's arms, while Yellow went on. "Okay, Black. Try to lift your left leg and cross it over the right."

Both lower halves crossed their legs, perfectly in synch.

"All right. Now try to uncross just one."

Black tried to focus on just one pair of legs, but the sensations were too similar. Both pairs of legs twitched a little as she tried to only move one, but it was no use. It was like trying to write different words with each hand at once.

"I can't keep them separate," said Black. "There's no way to tell the signals apart."

"How about this?" said Green. She set Black's upper half down on a table and went over to one of the stools, placing her hand on the right knee so her arm blocked the leg from uncrossing. "Try it now."

With a difference in sensation to focus on, Black was able to get a better grip on the feeling. She slowly lifted her other left leg and lowered it beside the right. The left leg that Green was blocking moved a little, but the more their positions differed, the better Black was able to distinguish them. Once one pair of legs was fully uncrossed, she crossed it in the other direction, and the pair Green was holding barely moved at all.

"Good!" said Yellow. "Nice adaptation. All right, since you're mirroring them anyway, I'd like to try to strengthen that." She turned the two stools to face each other. "I'd like you to lift the two legs that are crossing, and I want you to try to place the soles of the feet against each other."

The left leg of one pair rose up, as did the right leg of the other pair. As Black watched from across the room, she slowly guided the two feet until they met in the middle. She moved them back and forth, up and down, and around in a circle.

"There you go," she said. "What next? I should do the hokey pokey?"

"Not quite," said Yellow, "but hold that thought." She ran over to her and Orange's workstation and came back with a tangle of straps and buckles.

"Oh, boy," said Red. "Here we go."

"I have no idea what you're implying," said Yellow. She put the tangle in front of one of the stools and spread two loops of it in front of one pair of legs. "Okay, Black, I want you to step down and put your feet into the loops. Green, you'll want to help her."

"Yeah, I will."

"I mean that she'll need help keeping her balance without an upper half to steady herself," said Yellow. "Not that you'd want any excuse to grab her ass. But that too."

Black slowly stepped down from the stool, with Green there to steady her as well as to cop a feel, and she eventually got her feet into the loops, feeling around on the floor while she got as good a look as she could from the table. Now that she had more or less solid independent control over the two pairs of legs, she didn't have to worry about the other pair falling off its stool.

When the first pair was fully standing, Yellow lifted the straps up around her waist and cinched everything until it was nice and snug. It looked like a standard climbing harness, with thick loops around the waist and thighs, but there were a lot of extra straps that hung down around it.

"Oh, good," said Blue, her voice sarcastically flat. "Now you've given Green a leash to pull on."

"I'm not finished," said Yellow. "Hand on a second. Now the other one, Black. Step forward and spin around."

Black slowly got her other pair of legs standing, and she slowly turned around so the two pairs were again facing the same way. Yellow set the rest of the tangle behind her feet and opened the two loops again.

"Step back slowly."

Black aligned her front two feet with the rest of the harness, and Yellow pulled it up and around like she had before. She then placed her hand on Black's rear back and eased it down until it was horizontal, and she fastened it there with another loop of straps. Finally, she tightened the last set of hanging straps, pulling the two lower halves together until the cut surface on top of the rear one touched the rear end of the front one.

"Okay," said Yellow, barely able to contain her excitement. "Spin yourself around."

Now that all four of her legs were attached together, it was much easier for Black to keep her balance. She walked one pair to the right and the other to the left, and her enlarged lower half rotated in place to face the group.

"Okay, Green," said Yellow. "You get Black the rest of the way together, and I'll be right back." She rushed back to her workstation in a run that was almost a skip, while Green lifted Black's upper half from the table and set it back into place.

"Is this what this demonstration was about?" said Blue. "You wanted to make Black into a centaur?"

"Green, I know this is usually your line," said Violet, "but I think I'll want to ride her later."

"No, we can't do that yet," said Yellow. "Those straps are nowhere load-bearing. But we can do the next best thing!" She came bouncing over to the group carrying a bundle of brightly colored stripey fabric, which she wrapped around Black with Velcro so it covered the mess of straps.

"Oh, come on," said Red, unable to keep from grinning. "It even has a light-up reindeer on the front."

"Yep!" said Yellow. For the finishing touch, she stuck a red foam ball on Black's nose and a pair of plastic antlers on her head. "Merry Christmas, everybody!"

"Look out, everybody!" said Blue. "It's Santa's little helper!"

"Oh, come on!" said Yellow. "It wouldn't be Christmas without a tacky sweater!"

"Oh, thank goodness," said Black. "I thought the straps were the whole point. The sweater is a nice fit, though."

"It certainly goes nicely with the rest of the ensemble," said Green. She ran her hand along the length of Black's elongated back and cupped one of her rear buttocks. Black lifted a rear leg and rubbed it against Green's leg. The differences in sensation were getting easier and easier to manage.

"Okay, I think I'm ready now," said Orange. She came around the corner and froze when she saw Black. "Oh, wow, Yellow. That sweater looks even worse than you said it would."

"What's the matter?" said Black. "Aren't you feeling the Christmas spirit?" She turned back and forth, showing off both the sweater and her new extended wheelbase.

"Hey, if you want Christmas spirit," said Orange, "then have I got something to show you. Yellow, help me with this, will you?"

"Sure thing." The two of them disappeared around the corner again, and they came back carrying something long and green. It was about two feet tall by four feet long, it hung from two large holes supported by a pair of legs, and it was studded with at least two dozen of Red's arms, sticking out from it like a bizarre coat rack. Each one was gripped in a sort of cuff that held tightly to the shoulder, allowing the rest of the arm full range of motion.

"Well, that certainly explains the weird tingling feelings I've been having," said Red.

"Where did you get all those?" said Green.

"We built a second B-T device," said Orange, "one that can be more easily automated. When I borrowed each of Red's arms, I duplicated them before giving them back. Then all I had to do was program the new B-T to keep duplicating until I had the right number of each."

"Is this still part of the same experiment?" said Red. "You want to see if I can control specific arms at once?"

"Well, we can work on that eventually," said Orange, "but after seeing how Black turned out, I think I want to have my dessert first. Come on, Red. Give us a wave."

Red waved a hand at the board of arms, and half of it waved in synch with her. She tried again with the other arm, and the other half of the board followed.

"Awesome," said Orange. "Okay, now I want you to hold onto a few things for me."

"Fire away," said Red. She held out her hands, and all the copies arms opened up and reached out. Orange picked up a box and took out a series of shiny balls, placing them in some of the hands. Each time a ball touched a hand, it closed around it and held on.

"Good work," said Yellow. "It doesn't seem to take much difference in sensation to start developing independent control."

"Hush," said Orange. "We've had our science. Now is the time for joy and good cheer. Okay, Red, come on over and put your arms forward."

"Oh, no," said Violet. She put her hands over her mouth to stop from smiling too widely. "You didn't."

Red stepped toward the strange display and held her arms out in front of her. Orange and Yellow lifted the arm holder off of its pegs and put the holes over Red's attached arms, bending the whole thing until it wrapped around her. As they fastened it in place behind her, a flap of gaudy green fabric dropped down from the bottom, encircling Red completely. With a final dash of ceremony, Orange reached up and put a glowing golden star on top of Red's head.

"You did," said Violet.

"We sure did!" said Orange. "Merry Christmas, everybody!"

Red was wrapped all around in bright green, she was covered with outstretched arms, and here and there was the glint of a round bauble. She even had a star on her head to complete the look.

"You turned her into a Christmas tree," said Blue.

"Anyone can wear a gaudy sweater," said Orange. "It takes a true artist to really become the sweater."

"I do have to say," said Red, "we are getting a lot of good data about neuroplasticity with these tests. We might -"

"Hey, why don't we take a break from tests for a while?" said Black. She brushed one of her rear feet against Green's thigh. "We shouldn't be working at Christmastime. Who's up for a little Pin the Tail on the Reindeer?"

"Sounds good to me," said Green.

"I'll pin your tail!" said Red, chucking one of the glittery balls at Black. She hit her right in the cheek. Three more arms raised, their projectiles at the ready. Red grinned a toothy grin.

"Oh, you just go ahead and try it!" said Black. "I'll kick your ass, and I've got all kinds of ways to kick!"

"Bring it, Rudolf!" said Red.

Violet laughed and rushed over. "I've got twenty on the blond one!"

Yellow put her arm around Orange's waist and smiled. "This should be fun."