double quarter sister

When a person is a quarter sister both on the fathers side and also on the mothers side. The result of a wife swap.
1. Adam and Bertha has Edit. Bertha and John has Anna. John and Karen has Evelyn.
Edit and Anna are half sisters on Edits mothers side.
Anna and Evelyn are half sisters.
Edit and Evelyn are quarter sisters on Edits mothers side.
2. If also Adam and Karen has Maria.
Edit and Maria are half sisters on Edits fathers side.
Maria and Evelyn are half sisters.
Edit and Evelyn are also quarter sisters on Edits fathers side.
Hence Edit and Evelyn are double quarter sisters.
And Maria and Anna are also double quarter sisters.

When Edits dad Adam swaped wife with John she got a double quarter sister Evelyn, which she has never met since Edits mom Bertha hates Evelyns mother Karen.