The battle was long and well-fought, but at the end, Black and Red lay collapsed on the floor of the lab, out of breath. Red's harness of arms had come unfastened and lay half on and half off of her, the arms hanging down. Most of the arms had come completely loose during their good-natured scuffle, and they mostly lay on the floor around Black, but she had two of them in her hands. The star and the antlers had long since fallen off their heads, and Black's red nose was in some far corner of the room somewhere.

"Are you done playing now?" said Violet? "Have you two got your breath back?"

"Oh, man, that was fun," said Red. "That may be the best workout I've had in a while."

"So you're ... conceding, are ... you?" said Black, still panting. She had really put her all into their little sparring match.

"Fine, yes," said Red. "You win."

"Ha-hah!" said Black, raising her arms into the air. "To the victor, the spoils!" She held two of Red's duplicated arms as trophies.

"You need help getting up?" said Green.

"In a minute," said Black. "I'm just going to lie here for a minute first."

"About the spoils thing, though," said Blue. "It looks like your Christmas tree's starting to shed some needles, Orange. You have a plan for dealing with that?"

"Seriously," said Red. "It was fun for a but, but I really don't need twenty-four extra arms cluttering up the place." She gestured around the scattered pile of arms, and all of the hands moved in synch. She was winded enough that she was losing her concentration on keeping them distinct.

"Well, there must be something we can do," said Yellow. "I'm sure Orange and I can come up with something."

"I think I can do something about that," said Violet. "I've been working on an idea that I think could come in handy here."

"Oh yeah?" said Orange. "What you got for us?"

"Well, all of the extra arms are duplicates that you made of Red's original arms, right?" said Violet.

"Yeah," said Yellow.

"Well, I've been working on some new algorithms for the B-T device, and one of them ought to be able to reverse the effects of a duplication," said Violet. "The arms don't have any subjective experiences or individual perceptions or anything, so the reverse procedure should work no problem. It won't be quite enough, though."

"Why not?" said Red. "You couldn't just merge them back into my own arms?"

"In order to do that," said Violet, "we'd have to separate your arms again in exactly the same way as before so they match the duplicates precisely."

"Oh, yeah, you're right," said Orange. "I made that cut by hand. I wouldn't be able to do it the exact same way again. Hope you like having two extra arms, Red."

"Well, not necessarily," said Violet. "That was the other idea I had. I mean, unless Red really doesn't mind having two extra arms."

"Yeah, no thanks," said Red. "It's fun for parties, but I don't think I'd like it for always."

"Then yeah, it should be possible to disconnect the entanglement from Red," said Violet, "if it can be transferred to someone else."

"You're saying you can give Red's extra arms to someone else?" said Green.

"Maybe," said Violet. "I haven't tested it yet."

"Then I call dibs," said Green. "I believe I would like extra arms please. Four, if possible."

"So we're putting a hold on the Christmas party, then, huh?" said Black, getting her breath back. "Back to the science?"

"Well, if we're going to get this all cleaned up, then yeah," said Violet. "You guys gather everything up and take it over to Orange and Yellow's B-T, and I'll get my algorithm loaded into it."

Green helped Black to her four feet, lifting her under the arms since Black wouldn't let go of her trophies. Blue gave Red a hand up, and everyone started gathering up loose arms and carrying them around the corner to Orange and Yellow's workstation where Violet was busy making some adjustments, referring to her notes and making some brief calculations.

Once all of the extra arms were gathered together, sorted by rights and lefts, and once Black had been persuaded to relinquish her prizes, Violet selected two left arms and loaded them into the output chambers.

"Okay," she said. "Here goes nothing."

The doors closed, the machine hummed and clicked again, and the center door opened, revealing one single left arm.

"Okay, good," said Violet. "The math still works in both directions. I'll just plug this into Orange's automation protocol, and it should run the whole process in reverse. We should have just the two original copies left at the end."

"Yeah, but can you stop it before the end so there are four arms left?" said Green. "I believe I made a very reasonable request."

"Right, sure, fine," said Violet. "You got it, Green." She coupled her algorithm onto Orange's, and a set of conveyors and robotic arms began feeding arms into the B-T and withdrawing them when each cycle completed. Before long, only four arms were left.

"Thank goodness," said Red. "That feels better already. Now how about the second part?"

"Yeah, I'm pretty interested in that part myself," said Green.

"Well, we already know that a detached part will reattach on its own if you hold it against where it was cut off," said Violet. "Blue, you've played around with separation more than the rest of us. Have you tried swapping parts around at all?"

"A little," said Blue. "Enough to know that it doesn't work to just stick the part onto someone else. You remember, I was trying a lot of different stuff when I was working on the monofilament cutter. I needed to test it out in different circumstances."

"Yeah, that's it," said Yellow. "You had to test it. That was obviously the only reason."

"Well, what of it?" said Blue. "It's neat."

"So you're saying that the entanglement doesn't automatically collapse if you try it on a different person, right?" said Violet.

"Right," said Blue. "If you want two different quantum signatures to link together, you have to do more than just rub them together."

"I think I might be able to do that," said Violet. "That's where my other new algorithm comes in. It should be possible to link cells of different quantum signatures together by using the B-T to blend them together on a geometric level. If parts from two different sources are decomposed, shuffled together, and recombined, then the geometric shuffling should be enough to cause the quantum connection to assert itself. Once that happens, the original connection should dissolve."

"What if the original connection doesn't dissolve?" said Green. "Are we talking about a potential voices-in-my-head situation?" She suddenly seemed less excited about volunteering.

"Well, that's why it's called a test," said Violet. "It's valuable data either way."

"What if you tested the blending algorithm on two parts from the same source?" said Black. "Would that help you figure if the connection would transfer properly?"

"If they have the same source, then they connect on their own," said Blue.

"Only if you replace the part where it was," said Black. "What about if you put it in a different place?"

"It wouldn't be conclusive, but it should still help," said Violet. "If the new part felt like it was properly connected in the new location, then that would mean - oh." Violet suddenly realized. "Are you suggesting what I think you are?"

"Yeah, I'm kind of getting used to this," said Black. She ran her hands down behind her, along her second midriff. It was still held in place with straps against her rear end. "I think I'd like to keep it around."

"Do you have to cut a bare patch in your jumpsuit first?" said Red.

"No, I can account for that in the algorithm," said Violet. "That's an easy variable to control for. So you're up for it, then?"

"Sure," said Black. "Go for it."

"All right," said Violet. "Step on in." She held the input door of the B-T device open, and Black stepped inside.

"Okay," said Violet. "If this works, then the device will probably particulate you entirely, but everything except for the joined area should just be put back how it was. The area around the join will be shuffled and blended together so the cells of one part fade smoothly into the other. Are you ready to start?"

"All ready," said Black. "Hit me."

Violet began the procedure, and the door closed. There was a longer sequence of clicking, and the center door opened again. Black stepped out, loosened the straps, and let them fall to the floor. Where her original rear end had been was now a smooth transition into an extension of her back. She turned a slow circle to give everyone a look, making a few swaying motions back and forth to show off her new moves.

"How does it feel?" said Violet.

"It feels so smooth," said Black. "I think I'm going to like this."

"Hang on," said Green. "Before we can go on, we've got to test the most important thing." She stepped over to Black, placed her hands on Black's lower back, and pressed down, lifting herself onto Black and turning over so she was sitting sidesaddle on Black's back.

Black flexed her knees a couple of times to test Green's weight. "Well, how about that," she said. "That's actually not as hard as I thought it would be."

Green leaned against Black's shoulders and wrapped an arm around her. "Okay, I think I'm ready to give it a go now."

"You sure?" said Blue. "You don't want to trot around on your pony a couple of times first?"

"Okay, fine, spoilsport," said Green, hopping down to the floor.

"Besides, don't knock it till you try it," said Black. "You only have to ask."

"So where do you want me?" said Green.

"Just step into the chamber," said Violet. She laid Red's four extra arms on the floor of the chamber, and Green stepped in and stood between them. Violet made a few adjustments to the protocol on the screen, and then she pressed the button and the door closed. There were even more clicks and hums this time, but when the door opened, Green was standing there with four extra arms at her sides. The new arms were still sleeved in red, but there was a dark brown smear of color at the base of each one where the red sleeves blended into green.

Green stepped out of the chamber and gave her arms a test wave. Black ran her hands up and down the new arms to help Green start distinguishing them. "How about that, Red?" said Black. "You feel that?"

Red closed her eyes and held her arms still. "No, I don't feel a thing," she said.

"Green? You feeling anyone else trying to control your arms or mess with your brain?"

"No more than usual."

"There we go, then," said Black. "We have a successful test."

"So you're saying that we can swap parts back and forth now?" said Blue. She had snuck to the back of the group during the various procedures.

"Looks that way," said Red, turning to see what she was up to. She looked around for a second before she found Blue. "Really, Blue?" she said. "You couldn't wait, could you?"

Blue was leaning against a table with her head under one arm. The slicer was sitting on the table next to her, and her neck was sliced even with the top of the collar of her jumpsuit.

"What?" said Blue from down near her own hip. "It's handy! It gives me a useful vantage point when I'm testing the slicer on myself."

"We have cameras, you know," said Black.

"Nah, too boring," said Blue. "But you said we can swap parts, and we can reattach them in different places as well."

"And what?" said Green, gesturing with her middle left arm while she felt Black's shoulder with her upper right and stroked her back with her lower right. "You want your head put on backward or something?"

"No, I was just wondering if anyone wanted to swap," said Blue.

"Actually, it would be a helpful experiment, too," said Violet. "We've successfully transferred a spare part from one to another. We haven't tried swapping parts back and forth between people. If her head was switched to Red's body, what would happen to Blue's body? What would Red feel before she got swapped over? Now I'm curious about this."

"Wait a minute," said Red. "Why am I a part of this experiment all of a sudden?"

"It was just an example," said Violet. "I'll do it, if you don't want to."

"Well, I didn't say I didn't want to," said Red. "I'm just saying."

"So, it's settled," said Blue. "Red and I will switch bodies. Or is it me and Violet?"

"Maybe we should all three switch," said Violet. "It sounds like we're all open to it, and more data is more data."

"I think we're all missing a kind of important point," said Green, raising her upper left hand with a question. "If you all separate your heads like Blue's, what are we going to call you?"

"What do you mean?" said Blue.

"Oh, wait, she's right," said Red. "We call each other by the color of our jumpsuits. If we swap bodies, we'll be exchanging the one part of us that's actually distinguishable by eye. It'll get confusing real quick."

That actually threw all of them for a loop for a moment.

"Wait, that's an easy fix," said Violet. "All I have to do is divide everyone so part of the suit goes with the head. Like a deep V-neck or something."

"Oh, good," said Blue. "I can still watch from outside, then. Here, Green, hold onto this for me, will you?" She walked over to Green and handed her head over, and then she walked over to the table where she'd been leaning and grabbed the slicer like she maneuvered around the lab headless all the time. She probably did, for that matter.

"No, if we're going to be swapping, we can't make the cuts manually, remember?" said Violet. "We'll need to rig the slicer into the CNC so the cuts are identical every time."

"Well, go for it, then!" said Blue, calling out from Green's cradling hands while her body stood in front of Violet and gestured impatiently.

"It's your slicer," said Violet. "You rig the slicer into one of the Waldos, and I'll get the algorithm ready. Red, you're still up for it, right?"

"Sure," said Red. "I guess I wouldn't mind a change of clothes."

Blue took the slicer and replaced the handle with a mounting bracket so it could be attached to one of the lab's overhead robotic arms. As easily as she did it, it was easy to forget that her head was watching from a few feet away. Everyone started to wonder exactly how much time she had spent without her head on. When she was ready, Violet had the B-T programmed and waiting for her. Blue stood next to Red, and Violet pressed the start button on the console and quickly stepped next to the two of them.

Three large robotic arms with padded grips moved in and gripped each of their bodies from behind, and three smaller ones gripped their heads, or rather, Violet and Red's heads and Blue's neck stump. The slicer arm glided over and performed one smooth, identical slice on each of them, curving from shoulder to shoulder below their collarbones. Then the smaller arms lifted up, and Blue's body was positioned inside the B-T, along with Violet's head. The doors closed, and the machine started its clicking hum.

"Oh," said Blue. "Oh, that's weird."

"What is it?" said Green, tilting her head so she could look her in the eye.

"I just lost all feeling below the neck."

They looked over at the robotic arms. Violet's body was completely limp.

"Well, it makes sense," said Black. "Your body is kind of in a transitional period right now." She felt under Blue's jaw for a pulse. "Huh. You're still getting blood from somewhere. How's your breathing?"

"Kind of labored," said Blue, "like I'm under a big pile of comforters. I can still breathe, though."

"Weird," said Green. "We'll have to tell Violet when she comes out."

The door of the B-T opened, and Violet stepped out. She had a stripe of indigo swooping along her neckline where the two colors shaded together. She stepped over to Green and Black while her former body was loaded into the B-T with Red's head, and they filled her in on what Blue had told them.

"Interesting," said Violet. "Maybe you were getting a tentative link with my old body, or maybe you still have a lingering link with this one. We'll have to do some more in-depth testing later on. Hold on, here comes Red."

The door opened again, and Red stepped out, with a magenta stripe across her chest just like Violet's. She tried a few moves to see how her new body felt.

"Huh," she said. "It feels pretty much the same."

"Well, yeah," said Blue. "What were you expecting?"

"I don't know," said Red. "Something." She twisted back and forth. "Well, I guess if I had wanted something really different, I would have gotten an extra knee or some more necks or something."

Blue took a deep breath. "Okay, there we go," she said. "That's better."

The door opened a third and final time, and Red's body stepped out with Blue's neckline on top of it, with a purple border between the two. The body walked over between Violet and Red and put her arms around their shoulders.

"You want this back?" said Green, offering Blue's head back to her.

"Yeah, sure, thanks," said Blue, taking her head back but leaving it separated. "Now I have a whole new body to try out."

"What's the difference?" said Violet. "We literally have the same body. We're duplicates."

"Well, I won't know for sure until I try," said Blue. "That's just good science."

At that moment, they all realized that Orange and Yellow had been awfully quiet. They looked around and found the two of them talking something over at the far end of the room. Black and Violet went over to see.

"You two have something you'd like to share with the class?" said Black.

"Yeah, we've been talking over something we'd like to try," said Yellow. She looked up and saw Violet. "Wow, so that worked pretty well, huh?"

"As far as I can tell, yeah," said Violet. "The transfer seems to have worked pretty smoothly."

"So you can attach extra parts to a person," said Orange, "and you can attach different people's parts together. What about attaching two whole people together?"

Black and Violet gave each other a look. "What do you mean?" said Violet.

"We'd like to see what it would be like," said Yellow. "Could you use your new algorithm to bond our bodies together?"

Violet thought about it for a moment. "I mean, I guess I could. How bonded are we talking? I assume you want something more than just sticking you two side to side."

"Yeah, a little more," said Orange. "Could you bond us all the way together? Everything but the heads?"

Violet let out a slow breath. "Whoa. That's a lot of overlap. I don't know if the algorithm can blend that much."

"Well, it should be possible," said Black. "You'd be blending their bodies together in a one-to-one ratio, so the corresponding parts would match up. The only concern is how to accommodate so much extra mass."

"We could do it easily if the final result was just proportionately bigger," said Violet. "Does that work for you two? Would you mind being about a foot and a half taller?"

"Ooh, unexpected bonus," said Yellow. "Works for me."

"Then I'm willing to try it," said Violet. "Give me a minute to reconfigure the B-T, and then let's give this a try."

Violet went over to the console to adjust her figures, and Yellow and Orange joined everyone else to admire their alterations. Green got back on Black's back and just lounged, with her upper arms over Black's shoulders, her middle arms around her middle, and her lower arms stroking her front thighs. Yellow and Orange looked like they might have wanted to try something similar, but after all, they have something more extreme in mind already.

When Violet was ready, she opened the two output chambers and invited Yellow and Orange in. "I needed you to be in separate chambers for this one, since I don't think you'd both fit in the center chamber together in the right position."

"What's the right position?" said Yellow.

"I'll need you both to crouch down on the floor of the chamber," said Violet, "since you might end up too tall for the center chamber. We may want to rebuild one of the B-Ts if we want to explore this kind of thing in the future. This should do for now, though."

Yellow and Orange squatted down in their respecting chambers and hugged their knees as Violet made her final calculations. When she was done, she pressed the button, and the doors closed.

The machine clicked and hummed away, a little louder than usual, and when it was done, the center door opened, and Yellow and Orange stepped forward and ducked out of the machine.

Each of them had an area of jumpsuit around their neck in the original color, but the rest of their shared body was clad in a smooth shade of marigold. Their heads were the same size as before, but everything else was a bit bigger, from their shoulders down to their feet. They were almost seven feet tall.

The two of them took a deep breath at the same time, and then they let it out.

"That is weird," said Orange. "This'll take some getting used to," said Yellow.

"I think it worked," said Black.

"How do you feel?" said Violet.

"Do you feel the uncanny need to finish each other's sentences?" said Green.

"Oh, come on," said Yellow. "We do that anyway."

"It definitely feels different," said Orange. "I can control my own body parts, but I can feel her influence, too." Their right hand stroked up and down on their belly, and both of them smiled at the touch, as though each of them was giving the other a little special attention at the same time.

"Well, it wasn't as though they weren't working together all the time, anyway," said Blue. "At least now we have one less pair of hands around here."

"Says who?" said Green, waving at her with all six hands from on Black's back.

"Yeah, being shorthanded has never exactly been our problem," said Violet. "But I have lots of good data now, so I can start developing some more new algorithms. In fact," she said, snapping her fingers, "Yellow and Orange have just given me the idea for something really interesting..."