1.0 && task_state == 1.0) {
      button_state = 1.0
    } else {
      button_state = -2.0
    }
    console.log('click-button-sequence, button 1', button_state);
  });

  var L = core.randi(0, 118); var U = core.randi(0, 118) + 50;
  d3.select('#subbtn2').attr('style', 'position:absolute; left:'+L+'px; top:'+U+'px');
  d3.select('#subbtn2').on('click', function(){
    if (button_state == 1.0) {
      button_state = 2.0
    } else {
      button_state = -2.0
    }
    console.log('click-button-sequence, bu