X = 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
Y = 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
X ↔ Y

Ext-GCD(13, 13) :

i GCD Bezout AOdd : AEven :
A B ax ay bx by |A-B| A↔B Sx Sy ax
Sx'
ay
Sy'
A
A/2
ax
ax + Y
ay
ay + X
ax
ax/2
ay
ay/2
0 13 13 1 0 0 1
1 13 13 1 0 0 1 0
2 13 13 1 0 0 1 0
3 13 13 1 0 0 1 0
4 13 13 1 0 0 1 0
5 13 13 1 0 0 1 0
6 13 13 1 0 0 1 0
7 13 13 1 0 0 1 0
(1)(13) - (0)(13) = 13