text: #ifndef PACKINGWL_H
  #define PACKINGWL_H
  
  #include <stdio.h>       /* printf, */
  #include <stdlib.h>      /* malloc */
  #include <steinhardt.h>  /* */
  
  #include "utils/observables/Observer.h"
  
  class PackingWl : public Observer
  {
      public:
          explicit PackingWl(const char*, const char*);
          PackingWl(const PackingWl& orig);
          virtual ~PackingWl();
  
          double observe(const Box&, const std::vector<Shell>&);
  
      private:
          double calc_wl(const Box&, const std::vector<Shell>&, unsigned int);
          static DerivedRegister<PackingWl> reg;
  };
  
  #endif /* PACKINGWL_H */
  
  