With helpers:

Original

Cloned helper

Custom helper

Stacked:

We are draggables..

..whose z-indexes are controlled automatically..

..with the stack option.

Provide feedback to users as they drag an element in the form of a helper. The helper option accepts the values false/null (the draggable element moves with the cursor), true (a clone of the draggable moves with the cursor), or a function that returns a DOM element or jQuery object (that element is shown near the cursor during drag).