function ladder(height) {
  this.then(function ladderLater() {
    var block = this.getBlock();
    if (block.typeId == blocks.air || block.typeId == blocks.ladder) {
      this.box(blocks.ladder, 1, height, 1, true);
    } else {
      this.back()
        .box(blocks.ladder, 1, height, 1, true)
        .fwd();
    }
  });
}
*********************************************************************
### Drone.ladder() method

Creates a ladder extending skyward.

#### Parameters
height (optional - default 1) 

#### Example

To create a ladder extending 10 blocks high:

    var drone = new Drone(self);
    drone.ladder(10)

At the in-game prompt, look at a block and then type:    

    /js ladder(10)

A ladder 10 blocks high will be created at the point you were looking at.

#### Since 
##### 3.0.3
*