Ok, fine! Since you got the question right, I’ll return your mathboxes.
Here it is!
Wait… that’s it?
This is a mathbox with the “Plus 1” feature , but…
What about the ones with the “Minus 1” feature or the “Repeat” feature ?
I can’t return those yet.
The only ones I’m returning for now are mathboxes with the “Plus 1” feature .
Wait, what? No way!
But… you promised to return the mathboxes!
I said I’ll return the mathboxes…
But I never promised to return all of the features.
Nooo! You’re a liar!
Well, I’m a devil after all.
Looking for some other page?
So… what do we need to do to get all of the features back?
Well… on the previous pages, I asked you to reproduce the “Plus 1” feature using a lunchbox.
So, if you want the “Minus 1” feature or the “Repeat” feature back…
You must reproduce them using lunchboxes.
What!
We struggled to reproduce using a lunchbox. I don’t know if we can reproduce or …
If you can’t do it, you won’t get them back.
But… we need the “Minus 1” feature and the “Repeat” feature !
Without these features, we won’t be able to calculate subtractions or add/subtract large numbers.
I guess we have to try…
Don’t worry: Minion will give you a hint on how to reproduce those features using lunchboxes.
Yes. Let me give you a hint for reproducing the “Minus 1” feature .
To reproduce the “Minus 1” feature using a lunchbox, you need to fill each icon on the following lunchbox with a specific pattern.
Hmm… it looks really complicated.
It’s complicated, but if you do it correctly, you can use it to subtract from a number:
Now, try to guess what goes in each icon.
But… this lunchbox looks so complicated.
I don’t think we can do it…
The villagers were struggling, but it looks like Saya’s got an idea:
Hey guys, I think I have an idea.
What…? Saya, did you figure it out?
I don’t know if this is correct, but come take a look.
Hmm… I don’t think Saya’s going to be correct twice in a row, but let’s try anyway.
Ok. Let’s first combine it with a lunchbox that can be converted to .
If the result is , that means it correctly calculates , right?
Let’s run it with this lunchbox that can be converted to .
Here’s what happens if you combine them:
Ok, let’s run it.
Let’s run the above lunchbox. We’ll run it for a while and pause for an explanation.
Press Run . You can also skip to the next stopping point.
This is so complicated. My eye hurts!
You don’t have to follow all the steps with your eyes. Just glance over it. Save your eyes!
Hey guys, take a look! t and m are both pizza now.
The special rule applies, and the pizza in t changes to something else, right?
Press Next to apply the special rule.
The special rule just applied, and the pizza in t became sushi .
Now, let’s run it until the end.
The resulting lunchbox can be converted to .
So, by using Saya’s lunchbox,
Because it calculated , it’s a success!
Yay!
Wow…
Well: Just because you were able to calculate , it doesn’t necessarily mean that your lunchbox has reproduced the “Minus 1” feature .
It needs to be able to subtract 1 from any number.
That’s a good point…
For example: Can your lunchbox calculate ?
Let’s try it. Here’s a lunchbox that can be converted to .
Let’s combine it with my lunchbox:
Ok, let’s run it.
Press Run !
The resulting lunchbox can be converted to .
So, by using Saya’s lunchbox,
That means it calculated , so it’s a success!
Yay!
Grr…
Saya is correct. Her lunchbox does reproduce the “Minus 1” feature !
Awesome!
Wow… Saya, you’re a genius!
No, I’m just lucky. But anyway, we showed that the “Minus 1” feature can be reproduced using a lunchbox.
Note: Just like the last problem, this problem was very hard. We didn’t expect you to answer it.
As long as you can look at the answer and understand why it’s correct, you’ll be fine.
Note: There are other lunchboxes that can reproduce the “Minus 1” feature . Saya’s lunchbox is not the only solution.
If you’re curious, press “Continue reading” below. (It’s optional.)
Hey devil, we’ve reproduced the “Minus 1” feature using a lunchbox!
(Although it was Saya who did all the work…)
Grr…
As promised, give us the “Minus 1” feature back!
Fine, I will give it back to you!
Yay!
But I won’t give you back the “Repeat” feature yet.
If you want it back, you must reproduce it using a lunchbox too.
Seems difficult…. But we have Saya on our side. She’ll be able to solve it for sure!
We’ll see. By the way, we’re now done with the intermediate levels.
Let’s move on to the advanced levels next.
Alright, let’s do it!
You might be wondering: “I understand the puzzles, but does it have anything to do with Y combinator, which is in the title of this course (Y Combinator for Non-programmers)?”
Answer: You’ll learn about Y combinator on the advanced levels, which will start from the next page.
Also, a spoiler: Y combinator is actually a special kind of a lunchbox. You’ll soon find out what that means.
Let’s go to the advanced levels!