"Rocket Science"

The shot you are looking at is not a 'rocket science' but it is about 'necessity is the mother of invention'. This 'set up' is used by laborers for mixing gravel with cement(to make uniform mortar) and transporting mixed concrete to top of the building.
The crew of 'engine cum concrete' lifter is self sufficient in their business of construction.
The driver of this 'terrestrial rocket' is on his way towards new horizons of livelihood.