This is a bit confusing; Can someone please re-iterate it for me?

[Zeroknight]

For example, consider the turning of one face by 90 degrees:
C1 E1 C2
E4 E2
C4 E3 C3
→
C4 E4 C1
E3 E1
C3 E2 C2

The new corner state can be obtained via 3 swaps (swap C1/C4, swap C1/C3, swap C1/C3, swap C1/C2).

It looks like four swaps to me...

Thanks in advance

EDIT: Sorry, but somehow the edges got messed up...

 

[Lucas Garron]

It's 3. Try those swaps physically on your cube, in that order.
(And ignore one of the middle ones. I hope you weren't counting both.)

 

[Johannes91]

(swap C1/C4, swap C1/C3, swap C1/C3, swap C1/C2)
-->
(swap C1/C4, swap C1/C3, swap C1/C2)

 

[Zeroknight]

Sorry, guys (no I wasn't counting the middle ones). What I see is C1 goes to C2, C2 goes to C3, C3 goes to C4, and C4 goes to C1.


tbqh, I don't "see:" (swap C1/C4, swap C1/C3, swap C1/C3, swap C1/C2)
-->
(swap C1/C4, swap C1/C3, swap C1/C2)

 

[Johannes91]

tbqh, I don't "see:" (swap C1/C4, swap C1/C3, swap C1/C3, swap C1/C2)
-->
(swap C1/C4, swap C1/C3, swap C1/C2)

It's obviously a mistake in your quote, swapping the same pieces twice in a row would just cancel out.

Maybe this helps:

C1 C2
C4 C3

First swap: C1 and C4.

C4 C2
C1 C3

Second swap: C1 and C3.

C4 C2
C3 C1

Third swap: C1 and C2.

C4 C1
C3 C2

 

[Zeroknight]

Oh okay, Each piece swaps a total of three times with the others, thanks.

 

[Lucas Garron]

Oh okay, Each piece swaps a total of three times with the others, thanks.

Uh, no?

(Note that no matter how you do it, it's always an odd number of swaps, though.)