ah.. well it is me not being used for immutability...

# getting-started

[zucen.co]

ah.. well it is me not being used for immutability and avoiding nullability... then I need may be one more "Direction" like UNOPOSITIONABLE for Directions without opposit value to use instead of null and as default but it is little like dog catching its tail. Or is it generaly wrong to have in one group a value which does not satisfy same pattern -> defines opposite in this case?