code: function Vector( x, y ) {
  
          // enforce instantiation
          if ( !(this instanceof Vector) ){
  
              return new Vector( x, y );
          }
  
          // arrays to store values
          // x = _[0]
          // y = _[1]
          // norm = _[3]
          // normsq = _[4]
  
          /** internal
           * Physics.vector#_
           *
           * Private storage array for data.
           *
           * Do not access this directly. Private. Keep out.
           **/
          if (typedArrays){
              this._ = new Float64Array(5);
          } else {
              this._ = [];
          }
  
          if (x && (x.x !== undefined || x._ && x._.length)){
  
              this.clone( x );
  
          } else {
  
              this.recalc = true; //whether or not recalculate norms
              this.set( x, y );
          }
      }
docs: section: Special
  class Vectorish
  
  Any object with `.x` and `.y` properties.
  
  A `Vectorish` isn't really a class. In this documentation, when
  an argument is specified as a `Vectorish` it means either a true
  [[Physics.vector]] instance, or an object literal with `.x` and `.y`
  properties.
   
  new Physics.vector( x, y )
  new Physics.vector( vect )
  - x (Number): The x coordinate
  - y (Number): The y coordinate
  - vect (Vectorish): A vector-like object to clone
  
  Vector Constructor.