text: const Phaser = require('phaser');
  const humanImage = require('../assets/human.png');
  const wallImage = require('../assets/wall.png');
  const wallUpImage = require('../assets/wall_up.png');
  const grassImage = require('../assets/grass.png');
  
  const Human = require('./Human');
  
  const config = {
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    scene: {
      preload: preload,
      create: create,
      update: update
    },
    physics: {
      default: 'arcade',
      arcade: { debug: false }
    }
  };
  
  new Phaser.Game(config);
  
  const humans = [];
  
  function preload() {
    this.load.image('human', humanImage);
    this.load.image('wall', wallImage);
    this.load.image('wallUp', wallUpImage);
    this.load.image('grass', grassImage);
  }
  
  function create() {
    this.add.image(400, 300, 'grass');
  
    const staticGroup = this.physics.add.staticGroup();
    staticGroup.create(100, 100, 'wall');
    staticGroup.create(300, 300, 'wallUp');
    staticGroup.create(500, 500, 'wallUp');
    staticGroup.create(600, 200, 'wall');
    staticGroup.create(100, 400, 'wall');
  
    const humanGroup = this.physics.add.group();
  
    for (let i = 0; i < 1000; i++) {
      humans.push(
        new Human({ game: this, humanGroup, staticGroup })
      );
    }
    humans[0].infect();
  }
  
  function update(delta) {
    humans.forEach(human => human.update(delta));
  }
  