Sigh. He'll take a break, morph Andalite and do some tail-sparring, and then morph Yeerk so he can make another of his morph-capable rabbits morph and get stuck that way. This is a lot of morphing, but the rabbit will be ready for his next set of experiments tomorrow. 

This unsurprisingly results in weird and different failures rather than success, but he gets more skillful at dismantling worm morph setups and Gate-merging them into the mangled ones and connecting the spell without mangling things any more. He also does it while in his composite morph that has all the Gifts, to see if he can get anything out of his short-range Foresight. He doesn't think so, but maybe he just needs to teach himself how to pay attention to the right things with it. 

The day after that, Mhalir is available to talk to Cayaldwin again about morph research, if Cayaldwin wants. 

Cayaldwin does want that. It's so tragic how Mhalir was born a Yeerk; he'd have been a really good Andalite.

After his usual check-in meeting with Leareth, Mhalir can give Amanda the rest of the day and that night off, and head off in Leareth's head to talk to Cayaldwin. He really enjoyed their last session working on it together. 

Leareth follows better this time, enough to add a few comments of his own. He has to remind Mhalir at some point that lunch is a concept, and also that dinner is a concept, and also bedtime. 

Cayaldwin has made some progress and can get Mhalir quickly caught up on it and then ask him a bunch of questions about the new problems that this created. There's a lot of complicated visualization here and some of it is just in his head not the models but he'll try to convey it.

Bedtime is a stupid concept. Maybe Leareth could just hand Mhalir off to Cayaldwin and they could continue working?

...Really? Leareth is fine with that personally but he's very surprised, unless Cayaldwin just means he'll put Mhalir in a fishbowl and morph so he can Thoughtsense him, but Mhalir has less cognition available that way. 

<You defanged him, right, he can't do anything except see what I'm thinking and comment.>

:Yes. And use my Mindspeech if in my body, but I can modify that: 

:I think I would be able to grasp your visualizations better if I can actually just see them: Mhalir adds. With a lot of experience talking to both of them, he's just barely distinguishable from Leareth, some subtle Mindspeech-overtones difference. 

<Yeerks who can't control people aren't - it's an entirely different thing. If we'd met a species that did that I bet we'd never have gotten worked up about them at all. And you go to bed every night.>

:It is not my fault humans need sleep. You know, I thought Andalites needed sleep too: 

Mhalir extracts himself from Leareth's ear. 

Leareth removes the compulsion-loophole that lets Mhalir specifically use his Mindspeech; now he definitely won't be able to control anything of Cayaldwin's, just see his thoughts and comment on them. 

He holds him out. :Take good care of him: he says, half-teasingly. 

He reaches for him. <You know, I would not have predicted from first principles that you could get intelligence out of - that -> he says, and holds Mhalir up to his ear. 

:It really does not look like much. Then again, neither do our brains if removed from our skulls: 

Wriggle wriggle into his ear and Mhalir spreads out and he's there, seeing all of Cayaldwin's brain and orienting to it without actually being able to take control of anything. It's a little more stressful than with Leareth, he trusts Leareth a lot, but - worth dealing with the stress, he decided. 

Cayaldwin's mind is mostly formed around a loss so enormous that he has not even started processing it, does not believe it ought to be processed, would consider it ridiculous if anyone suggested that it would be better if his mind contained less of the loss and more of anything else. Almost every important memory from when he first learned speech is of his father: his father's questions, his father's puzzles, his father's impatience, his father's delight and joy and hunger, as Cayaldwin proved able to keep up, the way four older brothers had not been able to keep up, the way no one else in all of the world could keep up. Cayaldwin's father understood the world and hungered to understand the pieces of it he didn't, and his ambition was breathtaking and his scope was limitless and it seems like an error, an enormous unfathomable error, for him to have been made of atoms the same as everyone else in the universe, for him to have stop existing when they were destroyed the same as everyone else in the universe, it is an error that undermines the universe's entire claim to be a place worth living in, and Cayaldwin would have stopped, but then no one alive would understand, not even the broken partial fragments that fit in Cayaldwin's mind (because he's not as clever, he's not as important, he's not as valuable, he could keep up but he isn't actually good enough) -

- Cayaldwin is the only person who can do the things his father would have done, and it would be a betrayal, to stop doing them, so he works until he collapses exhausted and he morphs to fix the various things that go wrong with your body as you do this and he eats only because Andalites do not need to take separate actions, to do that, and when Matirin Fetched him off a ship that was about to explode he was angry, because -

- but it is better to keep as much of Firayar in the world as it will consent to hold, even though that's so so much less than there ought to be -

<Here's the thing I was trying to explain>, he says, thinking of planar maths.

...Wow. 

Mhalir absorbs it, slowly, while focusing mostly on the planar maths because that's what they're here to do, it's what Cayaldwin wants to be using his mind for, and it - seems to help, it doesn't ease the loss but he feels most-alive and least-broken when he's - doing what he sees as carrying on his father's legacy, keeping as much of him in the world as it will consent to hold - and it's always seemed like an unfathomable error to Mhalir for anyone to be made of atoms and cease existing when they're destroyed, it's why he wanted immortality in the first place... 

<I wanted to give it to everyone> he says at one point, hours later, in the middle of the night. <If I won the war. ...The Yeerks did not win the war, but - maybe this is close enough to winning, if it means we can solve this together, and - someday nobody will need to die for stupid reasons, ever again... Leareth said that was what you hoped for. Someday.> 

Mhalir presumably isn't imagining he could possibly have won a world with Andalites in it, he thinks without much heat. One of his father's research interests had been whether it was possible to escape to other planes, exist in some unhijackable form there, because the obvious alternative was annihilation. Or, well, there were discussions on discussion forums at home about whether, if things went badly enough, to try the thing Leareth called building a god. If they got it wrong it would probably transform the galaxy into worthless soup expanding outwards at the speed of light-in-every-plane, which it has been mathematically demonstrated is the speed of light to the twelfth, and people disagreed on whether this was worse than Yeerks, who did worse than turning the galaxy into worthless soup but did it slower than that.

Cayaldwin's plan now is to fix all the things that are broken about morph and probably add more failsafes against things happening to the storage mechanism in the Void, because if there are trillions of those they might start colliding with each other or something, and then everybody can exist in perfect safety and operate whatever construct body they like. It will be too late. The universe will never again have anything really beautiful and valuable in it. But it is what his father would have done.

Mhalir feels a surge of affection for Cayaldwin. And pain, and - something that holds regret but isn't quite shaped like guilt... So many losses they can never recoup. Some part of him has felt like it was too late ever since Seerow died. He knew the cost of war, of deaths in silently exploding ships miles away in space. He chose that over and over again. It doesn't make it hurt any less. 

<I wish I could have met him> he says, wistfully. <Your father. I wish - we could all have worked together on this - with Seerow, with Leareth... It is too late for so many things and - we could have built this decades ago> if he had been less stupid, some part of him screams, but even Leareth thinks the war was almost impossible for him to have resolved on his own, from the inside, even an adult Leareth transplanted into Mhalir's body probably couldn't have done it. <But what are we going to do except keep going and build it now.> 

And he changes the topic back to math. 

Math is much more interesting.

Math is very interesting and Cayaldwin is very smart and...also should probably sleep someday, ever, but Mhalir will keep going until he notices signs of Cayaldwin slowing down or getting foggier. 

Cayaldwin technically needs as much sleep as Leareth does but his focus on math seems to be the last thing to go, somehow, as he gets tireder.

Well, it's clearly about as natural as - walking, or breathing, for him. Being in a tired brain doesn't make Mhalir stupider exactly, he can push a host through quite a long time without sleep, but it's definitely noticeable. Possibly more subjectively noticeable to him than to Cayaldwin, who seems totally oblivious to his growing exhaustion. 

<...I did not follow that> he says eventually, apologetic. <Your brain is getting tired and it makes it harder for me. We might make faster progress overall if you get some sleep now and we keep going after?>

He's slightly exaggerating here but not by much. Also he's really curious what sort of math dreams Cayaldwin has. Sleep is important to mental acuity for a reason. 

Cayaldwin suspects he is being manipulated into sleeping but he's not really up for arguing about it. He trots over to the Andalite herd where they are mostly already asleep. <I have Mhalir> he tells Talik so no one morphs Thoughtsenser and notices and panics.