"I don't have more complex portals. Other than the interplanar one. The rest go to different distances and have different sizes but they feel the same. I can make a portal anywhere I can see within a mile, and the other side opens next to me."

Ahmose concentrates for a few seconds, and two man-sized, round portals open on two sides of the room. Then he yelps, and runs towards Puchuu gesturing frantically. "Don't touch them, please! The sides are very sharp and will cut anything that touches them. I forgot to tell you, I'm so sorry!!" This is so embarrassing and there's a hot feeling in his stomach at the terrible accident he nearly caused. "Just, um. Never touch the sides, that's all. Sorry. There's nothing else."

[Thank you for warning us before anyone got hurt! I would like to test that by hitting the side with a stick or something. Does that sound reasonably safe?]

"Ooh, nice..." Shining Black Lily mutters.

"Yes. The stick will be cut, that's all."

Puchuu valiantly tests this, with a stick that is fetched from... Somewhere. And then a metal rod, just for comparison. It investigates the cut points carefully. It also tries hopping through, being very careful about the edges.

Do the portals have 'fronts' and 'backs'? Does it look like something could pass through portals multiple times if it were long enough and pushed through in the right way.

Each portal has two sides, and each side is connected to a side of other portal. The two sides pointing towards each other are connected, and so are the 'outer' sides. You can push a long stick through the portals' inner sides several times, if it's angled so it doesn't touch itself.

[These could be incredibly useful! Is it tiring at all to maintain them? Could you maintain one without your attention?]

"I don't have to do anything to maintain it, I can even forget it's there." This is something he's pretty scared of, because if he forgets an open portal someone could find it and get hurt and find out he can make portals - that cat's out of the bag now. Ahmose never goes out of view of his portals if he can help it. "But I can only have a few open at once - more of them the smaller they are."

[I can think of two big ways to use your portals to make a lot of money for you. One of them is kind of dangerous. But we can talk about that later. Do you want to try going home now?]

Ahmose can also see the obvious and obviously dangerous way to use his portals for money!!! He hates that it's the first thing that comes to mind but it's indeed very obvious and he really really hates it and hopes he doesn't have to do it, but it might be a moral duty in which case he'll give his spell to the paladins in exchange for changing his memory so he can never know he invented it.

...

He really, really wants to go home.

"Yes, please." He closes the two portals. "I'm going to try to open a portal to the river-world again. A small one, that we can look through."

He concentrates and repeats what he did, as far as he can remember, and pours in all his power - the portal refuses to form for less, even though it's going to be smaller this time - until finally it opens.

It's dark and there's a wind blowing in, like the time he spent hours opening a portal-chain really far up to see all of the Middle Sea at once. Except there's nothing to see, this time, just a few points of light on a black background.

"That's outer space!" Black Lily declares with a gasp.

"Maybe it went off-target and ended up a few hundred miles above the river and looking away from the planet?"

They put a little mirror on a stick through it to look in the other direction. (The adventurer's friend!) Unfortunately, there is no planet anywhere nearby, and no obvious sun either.

"Um. I - don't know what's going on? I guess... I could be going to a new or different place every time, but..." He can't actually disprove that, except that it would be the worst portal spell ever. If his normal portals did that they would be completely useless.

"I can try again?" he offers. "I'll have to close this one, though, the planar portals take a lot more energy than the normal ones."

[Oh dear. I hope you will be able to go home. Go ahead! If you can't target a specific plane, that would be disappointing, but it's much better to know that in advance than have it be an unpleasant surprise.]

Ahmose also really hopes he'll be able to go home!!

The next planar portal also opens into space. He can't tell if it's the same space or not, because he doesn't have enough power to keep two planar portals open at once, and he's bad at mentally rotating the star-patterns.

Space a third time, and then just before he gives up in disgust - the portal opens on some kind of reddish... stuff... that fills it completely. It's moving, or maybe the faint light it shines with is moving, but the surface stays perfectly smooth and none of it comes through to this side of the portal.

"Oh no. I don't have a way to make the portals open only in clear space, do I." Please don't let him have cut anyone - THING, anything important, please please -

"Is that... Inside a star?"

[It would be much brighter if it was, so bright the environment ward would have to dim it! The pressure is very high though. According to the wards, the temperature is five hundred and seventy degrees Celsius, and the material is mostly Hydrogen.]

"A gas giant, then... Probably nothing alive to be harmed in a gas giant, right?"

[Almost certainly,] agrees Jasper. [Please mind your channeling!]

"Ah! Sorry, sorry, I was distracted by how cool this is-"

AAAAH A GIANT did he just murder an innocent giant!!! - no, wait, they're saying it's... some other thing and not alive?...

"But what if there was," Ahmose says, stuttering slightly with belated terror, "should I really be doing this? I want to go home but, but not if it kills someone!!" His imagination supplies a vivid image of his triumphant return home, stepping out of the bisected body of poor Mrs. Thekla. 

He's going to need a few minutes to calm down and... maybe keep trying... what do Lily and Jasper think?

[I understand your hesitation, Ahmose. It would be really bad to accidentally hurt or kill someone. If your portals really are appearing randomly distributed through possible space the chances of that are really really REALLY tiny, but they do exist!]

"Heeey Jasper, do I have to keep channeling the whole time?"

[You can stop now! The ward storage is close to full.]

Shining Black Lily huffs in relief and runs her hands across her skirt, nodding.

[I just wanted it topped up in case anything happened, like the gas planet. Ahmose, the risk of you hurting someone with a portal is not zero, but the risk of you hurting someone by walking around and tripping and falling on them is also not zero! Even if they appear on a planet, the chances of them appearing in the middle of a road or walkway in a way that people can't avoid it MUST be less than one in a thousand. Likely less than one in a MILLION. Even on a highly populated planet like Earth, densely inhabited areas cover about one percent of the land area, and most of that is empty most of the time. Just look at this house! If a portal appeared randomly inside this house, which is already vanishingly unlikely assuming it's random, it'd be really unlikely to unluckily hurt any of us three. I think it's best to look at risk in terms of probabilities and impacts! Your portals hurting someone is very high impact, but it's also very VERY unlikely! While learning and practicing with your portals carries a much higher likelihood, but lower impact, consequence: You learn more about what you can do and become more confident. It also carries a low likelihood, high impact benefit: If you find a world that needs help, or learn enough about your portals to do useful things with them, it would be amazing! It might not happen, but it might be worth trying on the off chance it DOES work!]

"And getting you home is important. And finding other worlds in need of help, might also be important. It's hard to look at and quantify long term benefits, especially if you won't be, uh, saving lives directly, but... There are some of those, if we learn more about your interworld portals and figure out a way to make them useful and safe?"

That makes sense and is exactly the sort of argument he's scared of and does NOT trust himself to make! It helps that it's someone else making it, but. A chance of one in a million of accidentally murdering someone every time he opens a portal actually sounds very bad!!

"I really hope I can learn to open them the same place as before," he agrees. "Only I can't see how, just now. It's like - the spell is the same every time, it doesn't have another component I could change, but I get a different place every time! Or a different plane, I suppose."

He somewhat reluctantly goes back to opening portals. The next one after the gas giant (which is not a gas-variant of giant, apparently, but a giant-variant of gas) is empty space again. The one after that -

Water, water as far as the eye can see, under a deep blue sky.

"Yes!! I did it!" He claps in triumph. 

[You don't have to use portals if you don't want to. I'm just trying to make the reasoning around it clearer.]

"You can argue yourself into knots with that kind of thinking, so maybe don't trust it blindly, though."

After the ocean appears:

[I'm recording all the protective enchantment's readings! Do you think we can take a sample of the water? Then you can try to come back to it again. And we can confirm it's the same place!]

Now he tells him he doesn't have to do it?

"Are you asking me? I... don't see why you couldn't take some of the water."

[Okay! I'm going to let a little bit in and collect it. Watch out for splashing!]

Puchuu prepares a glass vial on a stand from within a cabinet, then does things with the wall sigils, and the invisible wall of force flush with the portal, which previously had no water coming through- Blips, letting in a hearty splash.

[We can learn things about this world by analyzing the water!]

"What kind of things? And how long would it take? All I know is that it was really salty." Wouldn't it be easier to look for a fish or something?

"Maybe you can divine if the water I spilled in the garden" (he's still embarrassed about that) "is from the same place as this?"

"I can't do divination stuff," Black Lily comments. "But the labs and spectrometers and stuff are sort of like divination."

[That's a good idea. We should collect some of the water still soaking your robe, and more samples through the portal.]

"We can tell what kinds of materials are dissolved in it, with enough samples. How much salt, how much other stuff. Spectrometers use light absorption and emission to detect trace amounts of various things. Salt glows slightly differently from dissolved calcium or whatever."

Lily may claim she's a sorcerer but they're clearly being wizards right now! This is so cool.

SCIENCE!! By which we mean careful sample collection and labeling, proceeds apace.

Ahmose will wait until they're done with the portal, and try to ask questions whenever they seem distractable! Is there something unusual about this salt? (Beyond how much of it there is.)