Architecture decorated with architecture
One thing that's always puzzled me about Beḷūr and Haḷēbīdu is that though they arguably represent the last pinnacle of the Deccan Dravida architectural style, none of the tour guides there actually seems to understand the design of the temples themselves. Sure, they're dramatic to look at, sure, they're a star-shape, but why? A brief explainer.
A Hoysaḷa temple consists of three basic components.
1st, the vestibule, the transitional space controlling your access from the environment outside to the temple interior (my thanks to Apoorva Lakshmi for pointing this out - she also who also very kindly took the first photo here). 2nd, the pillared hall, dim and mysterious, light trickling in through perforated jali screens.
Seen from outside, these two components make a staggered square, like steps moving away from you.
Finally, the shrine, in pitch dark lit by flickering oil-lamps, around which the iconic star-shape shrine is made.
As you can see from the design of a modern Hoysaḷa-style shrine by Adam Hardy, this design was made by rotating a square around its central point.
Adam Hardy has outlined the evolution of the star-shape in the Deccan from a basic square. The logic is aedicular, meaning that the building is really made of smaller buildings. Observe how a tier identical to the lower one is added to (a) to make (b). Then, observe how small dome-shaped aedicules - similar to the top of (b) - are added to the first tier to make (c). Observe how the shape of the temple grows incrementally more complex as mini-buildings and pilasters are added to it, creating a staggered square of great complexity, dancing with the rhythm of these mini-buildings along its axes of symmetry, But as the staggered square grows increasingly complex, it begins to lose some of its coherence, thus leading to the logical final step: its transformation into a rotated square, or a star.
You may have noticed in the plan provided above (the second image) that the star is not complete. Along its auspicious cardinal directions, it retains staggered square projections. These projections are decorated with elaborate shrines, the gods within them chosen carefully to contribute to the temple's overall iconographic programme.
But it's really the walls of the star where you can see the architects of the Deccan flexing their creativity - observe the threefold division of the temple above the base.
The plinth is decorated with bands of sculpture, like wreaths garlanding the entire structure. Above it is a row of mini-shrines giving you a glimpse at the enormous variety of designs with which these people were proficient. Then a row of sculptures, again enshrined under temple-spires, and finally, bold, sharp pillar-forms holding up the roof. There would have been a similarly stellate spire above these temples, a brick-and-mortar construct that collapsed in the 20th century. The overall picture is truly imposing.
Architecture decorated with architecture: the aesthetic principle of alaṁkāra perfectly expressed.