Which one of the following statements related to architecture is not correct?

Option 3 : Pietra dura was a technique to place horizontal beams across two vertical columns.

'Pietra dura was a technique to place horizontal beams across two vertical columns' is not a correct statement related to architecture.

• Monuments provide an insight into the technologies used for construction. 
• Between the seventh and tenth centuries architects started adding more rooms, doors and windows to buildings.
• Roofs, doors and windows were still made by placing a horizontal beam across two vertical columns, a style of architecture called “trabeate” or “corbelled”.
• The trabeate style was used in the construction of temples, mosques, tombs and in buildings attached to large stepped-wells (baolis). 
• The following technological and stylistic developments are noticeable from the 12^th century:
  • Arcuate:
    • The weight of the superstructure above the doors and windows was sometimes carried by arches. This architectural form was called “arcuate”. 
    • The “keystone” at the centre of the arch transferred the weight of the superstructure to the base of the arch.
  • Limestone: 
    • Limestone cement was increasingly used in construction.
    • This was very high-quality cement, which made construction of large structures easier and faster.
• It was during Shah Jahan’s reign that the different elements of Mughal architecture were fused together in a grand harmonious synthesis.
• Behind the emperor’s throne were a series of pietra dura inlays that depicted the legendary Greek god Orpheus playing the lute.

• Pietra dura is an architectural technique in which coloured, hard stones placed in depressions carved into marble or sandstone create beautiful, ornate patterns.

Based on the above given points, we can conclude that the following statements related to architecture is not correct:

Pietra dura was a technique to place horizontal beams across two vertical columns.