Pooooke?

His finger can go inside the aperture if he wants it to. There's nothing there.

"Maybe it only works if you do it but there's some kind of hole in it here." He hands it back.

He accepts it then pokes a finger into the hole. Then two fingers. Then his whole hand. Then his whole arm. 

"...I think I came with a bag of holding of my own," he says, his right arm disappeared up to the elbow into the shield.

"- oh wow that's so cool! Definitely makes up for having to buy a sword."

He pulls his arm back out, checks that it's undamaged, then taps the other side of the shield again. "Still feels like there must be something else inside. If I just try doing things should I be able to figure them out? Like for any kinds of personal powers and stuff."

Yes.

"Okay well I can try doing..." He's being such a lying liar who lies but if he'll rewind—

Yes.

—wait hold on he didn't know his shield had a cool clockwork thing that activated when he rewound time! That's so aesthetic! 

"Okay I can rewind time! Like less than the whole month apparently!"

"Well, that's good, you wouldn't want to scrap a whole month every time something bad happens."

"Well worst-case scenario I'll be able to just see how a fight will go and report back on it. I just wound back to my own body though, I wonder if I can do more time travelling than just that."

"Like a time-turner in Harry Potter?"

"—oh I hadn't even thought of that possibility. Uh, okay, so if another me appears in the bathroom right now then I'll go in the bathroom after he leaves to turn back time?" he suggests, and looks at the bathroom door hopefully.

Well, bathroom door?

"Okay guess not then," he says, pouting a bit.

"Maybe you can do it but you didn't successfully initiate a stable loop and have to avoid your other selves till you know you're capable of it?"

"Oh good thinking. Okay I'm gonna go... uh... oh I know, I'm gonna go out and roofhop in one direction for thirty seconds then try to go back in time and drop down to the street level and come back—no, and keep running in the same direction for thirty seconds, and then double back. So I should be back in a minute and a half if I succeed?"

"Have fun!"

"Thanks!" He totally should be able to hop off this apartment's window, though, so he'll do that instead. Hup.

Hop hop hop wheeeeeee roof hopping is so much funnnnnn! Honestly he doesn't know why he was so lukewarm on the idea before, being a magical boy is turning out great for him. He counts up to thirty, then he tries to do—some kind of motion in his mind, it actually feels really weird how he can tell there's a thing he can do that's different than the rewind thing, and if he tries that—

His clockwork buckler activates again and then everything stops. The cars, the birds, the clouds, the people. The entire world freezes around him, and he's the only one moving.

...okay, that's. Not a time-turner, which is a bummer, but maybe practically speaking this is better? He hops down to street level but rather than running he starts making his way back at a walk, looking at everything and everyone.

Everything and everyone is frozen in time. It looks kind of how one would expect it to, if this were an anime: drops of water floating midair, people and things in the middle of movement, unable to continue their trajectory. What's weirder, though, is that the world looks... bluer? In whatever direction he walks in, and redder in whatever direction he walks away from. It's subtle, but it's there.

Is that a physics thing? Yutaka thinks that might be a physics thing.

Wicked.

Now if this were an anime, he'd either be completely unable to affect anything, or stuff he touches would start moving with him. Which one will it be? He'll walk until he finds a pebble or something and try to pick it up.