let goingZDirection = 0;

    let chunkOriginalWidth = chunksContainer.width;
    let chunkOriginalHeight = chunksContainer.height;

      if (this.keyboard.justUp[">"]) {
        goingZDirection = 0;

      if (this.keyboard.justUp[">"] || this.keyboard.justUp["<"]) {
        // reset

        chunksContainer.width = chunkOriginalWidth;
        chunksContainer.height = chunkOriginalHeight;

      if (this.keyboard.justUp["<"]) {
        goingZDirection = 0;
        chunksContainer.alpha = 1;
      }
      if (this.keyboard.justDown[">"]) {
        if (goingZDirection != -1) {
          chunksContainer.alpha = 1;
          goingZDirection = -1;
        }
      }
      if (this.keyboard.justDown["<"]) {
        if (goingZDirection != 1) {
          chunksContainer.alpha = 1;
          goingZDirection = 1;
        }
      }

          chunksContainer.alpha = 1;
          // start the process to render next z level
          backdrop.tint = 0xDDAADD;

          zLevel = new RenderedZLevel(
            new ZLevel(this.randomSeed, zLevel.zLevel.z - 1),
            this.config.onFocusedNodeChange
          );
          // zLevel = preloadedZLevelDown;
          // preloadedZLevelDown = new RenderedZLevel(
          //   new ZLevel(this.randomSeed, preloadedZLevelDown.zLevel.z - 1),
          //   this.config.onFocusedNodeChange
          // );
          chunksContainer = zLevel.container;
          this.actionStage.addChild(chunksContainer);
          chunksContainer.x = this.app.screen.width/2;
          chunksContainer.y = this.app.screen.height/2;

          setTimeout(() => {
            zLevel = new RenderedZLevel(
              new ZLevel(this.randomSeed, zLevel.zLevel.z - 1),
              this.config.onFocusedNodeChange
            );
            // zLevel = preloadedZLevelDown;
            // preloadedZLevelDown = new RenderedZLevel(
            //   new ZLevel(this.randomSeed, preloadedZLevelDown.zLevel.z - 1),
            //   this.config.onFocusedNodeChange
            // );
            chunksContainer = zLevel.container;
            this.actionStage.addChild(chunksContainer);
            chunksContainer.x = this.app.screen.width / 2;
            chunksContainer.y = this.app.screen.height / 2;
            backdrop.tint = 0xFFFFFF;
          });

          // start the process to render next z level
          chunksContainer.alpha = 1;
          backdrop.tint = 0xDDAADD;

          zLevel = new RenderedZLevel(
            new ZLevel(this.randomSeed, zLevel.zLevel.z + 1),
            this.config.onFocusedNodeChange
          );
          // zLevel = preloadedZLevelDown;
          // preloadedZLevelDown = new RenderedZLevel(
          //   new ZLevel(this.randomSeed, preloadedZLevelDown.zLevel.z - 1),
          //   this.config.onFocusedNodeChange
          // );
          chunksContainer = zLevel.container;
          this.actionStage.addChild(chunksContainer);
          chunksContainer.x = this.app.screen.width/2;
          chunksContainer.y = this.app.screen.height/2;

          setTimeout(() => {
            zLevel = new RenderedZLevel(
              new ZLevel(this.randomSeed, zLevel.zLevel.z + 1),
              this.config.onFocusedNodeChange
            );
            // zLevel = preloadedZLevelDown;
            // preloadedZLevelDown = new RenderedZLevel(
            //   new ZLevel(this.randomSeed, preloadedZLevelDown.zLevel.z - 1),
            //   this.config.onFocusedNodeChange
            // );
            chunksContainer = zLevel.container;
            this.actionStage.addChild(chunksContainer);
            chunksContainer.x = this.app.screen.width / 2;
            chunksContainer.y = this.app.screen.height / 2;
            backdrop.tint = 0xFFFFFF;
          });