s_checked = d3.select('#ch'+i)[0][0].checked;
      r += is_checked === checkboxData.toclick[i] ? 1.0 : -1.0;
    }
    task_state = r == checkboxData.elems ? 1.0 : -1.0;
    console.log('click-checkboxes-transfer', task_state);
  });

  // click-button-sequence
  var button_state = -1.0
  var L = core.randi(0, 118); var U = core.randi(0, 118) + 50;
  d3.select('#subbtn1').attr('style', 'position:absolute; left:'+L+'px; top:'+U+'px');
  d3.select('#subbtn1').on('click', function(){
    if (button_state == -