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(15, 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 15 13 1 0 0 1
1 15 13 1 0 0 1 2 0 1 1 1 1 1 14 16 7 8
2 1 13 7 8 0 1 12 1 7 9 7 9 6 20 24 10 12
3 6 1 10 12 7 8 5 3 Even Even 5 6
4 3 1 5 6 7 8 2 0 12 14 12 14 1 Even Even 6 7
5 1 1 6 7 7 8 0
6 1 1 6 7 7 8 0
7 1 1 7 8 6 7 0
(7)(15) - (8)(13) = 1