I saw this sentence in Cypher, in which game you try to break various cyphers.

Swap columns 1/2 and 3/4 of each block. 1001011110110101
Round 1 key: YS
Round 2 key: BX
Basic Encryption Standard
To encrypt;
[] Arrange text and key into 4x4 blocks.
[] Swap columns 1/2 and 3/4 of each block.
[] Substitute (XOR) text block using key block.
[] Shift rows of text block +0, +1, +2, +3.
[] Complete 2 rounds

I didn't know whether it meant "Swap the 1st column for the 2nd column and the 3rd column for the 4th column" or "Swap the 1st column for the 3rd column and the 2nd column for the 4th column". I checked some websites explaining how to use slashes in English sentences, but nothing similar was found.

Actually, it intended to mean "Swap the 1st column for the 2nd column and the 3rd column for the 4th column", but I'd like to ask native English speakers just in case: Does this sentence CLEARLY mean "Swap the 1st column for the 2nd column and the 3rd column for the 4th column"? Or, is it ambiguous even for native English speakers?

Thank you!

  • 1
    It's not written very clearly. If it is from a puzzle game, that may be intentional so that you might have to try one way and if that doesn't work, try the other way.
    – ColleenV
    Nov 29, 2023 at 15:49
  • @ColleenV Ah, it makes sense. Actually, I wondered whether the "Shift" in the problem statement meant right shift or left shift. So it's likely that the creator of the game intentionally wrote the problem statement ambiguously. Thank you for your comment!
    – rei727
    Nov 29, 2023 at 16:06
  • typically a + means "increase" so, a shift in English would almost always go from left to right. Shifting rows positively most likely means moving down from the top because of the way the blocks are numbered (go from smaller coordinates to larger) but it could also mean moving from the bottom toward the top (a higher position on the page and the rows aren't explicitly numbered). I think it's vague on purpose.
    – ColleenV
    Nov 29, 2023 at 16:14
  • @ColleenV I didn't know that "a shift in English would almost always go from left to right." As you explained, "Shift" meant a right shift in the game. Thank you!
    – rei727
    Nov 29, 2023 at 16:43
  • 1
    It's because we read English left to right, so to the right in text is "increasing" or further away from the beginning. It's very unusual to have the beginning on the right side of a diagram.
    – ColleenV
    Nov 29, 2023 at 16:55

1 Answer 1


First of all, you're right that it's not very clear. All of these instructions are written with very few words and are not always clear (especially the next line!).

I think your guess is right that in means "swap column 1 for 2, or 2 for 1, and similar for 3 and 4," simply because that's the simplest meaning to take. If the author meant "swap 1 for 3 and 2 for 4 and so on," that would be an even less clear meaning.

Slashes aren't often used in English writing, and it's a pretty good rule of thumb that you can make meaning clearest (and make reading easiest) by avoiding them. But there are some patterns to how they're often used. They often mean "and" or "or," like if a thing has two functions or two names. "This is an indoor/outdoor carpet": it can be used in either role. Sometimes we might even say the word "slash" out loud: "I'm the club's treasurer slash secretary": I fill both roles. Or sometimes it's used with when there are multiple options: "That's an on/off switch." It can't be both at once, but it can be either on or off.

This idea of two interchangeable states might be what's behind the author's choice of a slash when they mean "1 for 2." But ultimately, I wouldn't worry too much about this screenshot; it's not written terribly clearly and isn't a great model to copy.

  • So it's an unclear sentence and not-so-good use of slashes, as I expected :( Thank you for your kind explanation!
    – rei727
    Nov 29, 2023 at 21:37

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