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(4, 9) :

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 4 9 1 0 0 1
1 4 9 1 0 0 1 5 2 10 4 5 2
2 2 9 5 2 0 1 7 1 14 6 7 3
3 1 9 7 3 0 1 8 1 7 4 7 4 4 16 8 8 4
4 4 1 8 4 7 3 3 2 Even Even 4 2
5 2 1 4 2 7 3 1 1 Even Even 2 1
6 1 1 2 1 7 3 0
7 1 1 7 3 2 1 0
(7)(4) - (3)(9) = 1