890678 ak: 98cd 95
First two octets of ak are all
the 16 groups XORred together.

The last octet is the same
as in shortenedkode:
Zeroes are dots here.
See there are 5 all-zero
and 9 non-zero groups.
16 groups are all together.
The rest is easy. There are
exactly 16-9-5=2 mixed.
Those mixed you shall
see easily:
.... .... .... ....
.... f699 1578 4.96
6243 9ed3 358a 3698
52.1 5619 7e8a beaa