anchor.diff:    <tr><th><code>30 * * * *</code></th><td>Every 30th minute of every hour</td></tr>
     <tr><th><code>0 */4 * * *</code></th><td>Every 4 hours</td></tr>
     <tr><th><code>0 */12 * * *</code></th><td>Every 12 hours</td></tr>
  +  <tr><th><code>0 0 */2 * * +01:00</code></th><td>Every other day at midnight UTC+1</td></tr>
     <tr><th><code>0 8 * * *</code></th><td>Every day at 8am UTC</td></tr>
  +  <tr><th><code>0 8 * * * America/Vancouver</code></th><td>Every day at 8am in Vancouver</td></tr>
     <tr><th><code>0 16 * * SUN</code></th><td>Every Sunday at 4pm UTC</td></tr>
     <tr><th><code>0 0 * * 1-5</code></th><td>Every weekday at midnight UTC</td></tr>
     <tr><th><code>0 0 1 */2 *</code></th><td>Every other month, at midnight UTC on the first day</td></tr>
  
positive.code:  │ │ ┌───────────── day of month (1 - 31)
   │ │ │ ┌───────────── month (1 - 12)
   │ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday)
   │ │ │ │ │
   │ │ │ │ │
   * * * * * 
  ```
  
  Examples:
  
  
negative.code: 
  ### Crontab time syntax
  
  Intervals can also be defined using a variant of the crontab time syntax:
  
  ```
   ┌───────────── minute (0 - 59)
  