Facts in A Valediction: Forbidding Mourning
If you were drawing a circle with a mathematical compass, you would “fix” one foot to one point on a piece of paper and then rotate the other foot around it in order to draw the circle. The “free” foot that is moving, always circles around the fixed foot because they are attached.
In the Petrarchan sonnet tradition, the speaker would often break his love object into her distinct parts in order to describe each one as perfect and beautiful. He would focus on her physical parts and compare them to greater concepts, such as her lips red as a rose. Here Donne uses a catalogue of human parts as an anti-blazon that pushes back against the Petrarchan tradition in order to declare that their love does not care about these physical markers (or this poetic representation of perfect love).