anchor.diff:            </div>
           </div>
         </div>
  +      
  +      <div class="control-group">
  +        <label class="control-label" for="input-length-milestones">
  +          How long is each period, in days?
  +        </label>
  +        <div class="controls">
  +          <input type="number" id="input-length-milestones" required="required">
  +        </div>
  +      </div>
  +    
         <div class="modal-body">
           <div class="control-group">
             <label class="control-label" for="input-number-milestones">
  -            How many milestones should we create?
  +            How many periods should we create?
             </label>
             <div class="controls">
               <input type="number" id="input-number-milestones" required="required">
  
positive.code:         
          <div class="control-group">
            <label class="control-label" for="input-start-milestones">
              What day should the first milestone start on?
            </label>
            <div class="controls">
              <div class="datepicker-past input-append date">
  
negative.code:   <div id="lesson-plan-multi-milestone" class="modal hide fade" data-backdrop="static">
      <form class="lesson-plan-milestone-generator-form">
        <div class="modal-header">
          <h3>Period Generator</h3>
        </div>
        <div class="modal-body hidden">
          <div id="modal-loading">
  