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, 7) :

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 7 1 0 0 1
1 15 7 1 0 0 1 8 0 1 1 1 1 4 8 16 4 8
2 4 7 4 8 0 1 3 2 Even Even 2 4
3 2 7 2 4 0 1 5 1 Even Even 1 2
4 1 7 1 2 0 1 6 1 1 3 1 3 3 8 18 4 9
5 3 1 4 9 1 2 2 0 5 11 5 11 1 12 26 6 13
6 1 1 6 13 1 2 0
7 1 1 1 2 6 13 0
(1)(15) - (2)(7) = 1