Eastenders: How are Bianca and Pat related?

Whilst Bianca is the daughter of Pat's son, making Bianca Pat's granddaughter, there is another route by which Bianca and Pat are related. This is complicated, so bear with me. Pat used to be married to Frank Butcher, played by the late Mike Reid, who was Ricky Butcher's dad. Ricky used to be married to Bianca. So Ricky was Pat's stepson, making Bianca Pat's step daughter-in-law. Confused? I am!