The indigenous builders of the Taj Mahal fully understood the deceptive nature of the human eye. They knew that the reality and its perception and interpretation thereof differed. The plinth of the main tomb is 2'10'' high on an average. But the height varies at different places, particularly the central point between two piers being in each case 0.5" to 0.7" higher than the sides. This convexity has deliberately been given to the plinth in the centre of each arch, or else the building would have appeared as if it were falling down! The facades are not exactly at a right angle with the plinth, but are slightly inclined.
The finial is a stupendous crowning feature which measures nearly 10 meters!! The architect fully anticipated the apparent size which a finial would present from such a great height. It has therefore been very ingeniously been planned. These features of construction demonstrate the ability of the Indian architects to reconcile the illusionary effects created by distance and light