The project has been tied up in political and legal 'knots' for years. [=nothing has happened with the project for years because of political and legal problems]
The mayor 'tied himself in knots' answering a touchy political question. [=he answered it in a confused or unclear way]
She 'knotted' a sweater around her shoulders. [=tied the sleeves of the sweater together around her shoulders]
(..) if you've never been in love before? 'Cause I feel it. Where? In my stomach. It's all warm. I always had a knot there, and now it's gone. Mathilda, I'm glad you don't have a stomachache anymore. I don't think it means anything. (..)1994 Léon: The Professional