eTree;
        if (!toolbox) {
          console.error('Toolbox not found; add a toolbox element to the DOM.');
          return;
        }
        var blocks = toolbox.getElementsByTagName('block');
        for (var i = 0; i < n; i++) {
          var blockXML = blocks[Math.floor(Math.random() * blocks.length)];
          var block = Blockly.Xml.domToBlock(blockXML, workspace);
          block.initSvg();
          block.moveBy(
            Math.round(Math.random() * 450 + 40),
            Math.round(Math.ra