code: func (nm *nmVertex) equalToVertex(other *nmVertex) bool {
  	for i, n := range nm.vars {
  		if n != other.vars[i] {
  			return false
  		}
  	}
  
  	return true
  }
docs: // equalToVertex will compare this vertex to the provided vertex
  // to determine if the two vertices are actually identical (that is,
  // they fall on the same point).