This is the simple chart WITHOUT ADX candles indicator.
and this is the same chart WITH ADX candles indicator.
As you can see, this indicator changes the candles with different colors based on the strength of ADX and DMI.
No need of any further explanation. The chart itself says everything.
You may download this indicator from here.
The above link will give you file in compiled format, supported by MetaTrader4. In case of any problem, you may download the same in zip file also from here.