Using .animate with :lt() Selector

Using .animate with :lt() Selector

Hi all,

I have the following working code which is executed onclick:
  1. $waste.append($stock
  2. .children('.container:lt(3)')
  3. .css( 'left', function(i) {return ['0rem', '2rem', '4rem'][i];})
  4.        );

It shows 3 div's positioned 0, 2 and 4 rem from a left div border. This all shows up correct. 

BUT....I don't want these 3 DIVs just to appear on their given location, I want to move them to that location. How to do this? I've tried things like:
  1. $waste.append($stock
  2. .children('.container:lt(3)')
  3. .animate( left: function(i) {return ['0rem', '2rem', '4rem'][i];}, 200)
  4.        );
But this doesn't seem to work. Anyone has an idea how to achieve this?

Thanks a lot