code: function (pos) {
        if (!pos) {
          throw new Error('Body position is required');
        }
        var body = createBody(pos);
        bodies.push(body);
  
        return body;
      }
docs: Adds body to the system at given position
  
  @param {Object} pos position of a body
  
  @returns {ngraph.physics.primitives.Body} added body