Aby var & somali
The difference between an abyssinian (aby) and a somali is nothing else than the length of its fur. L meaning short fur (dominant) and l being long (recessive) gives us LL for the aby, ll for the somali and Ll for the mix, the aby var.
This results in that the offspring of a somali and aby becomes short haired but with one of the alleles being long haired, hence the name aby var.
Breeding a somali with an aby var results in 50% aby vars and 50% somali.