HELM FORT ECHO DESIGN PROCESS / Yaren Öztürk
I started this project by researching the history of the castle. Kayseri Castle, which was probably started to be built during the Roman period, was given its final form by the Ottomans. This castle, which was built for defence purposes at the time, has become a touristic area as a symbol of cultural heritage in the last century. While designing this project, I was inspired by the fact that the Romans, the owners of the first traces of the castle, built the castle for defence purposes and the amphitheatre that we can see in most of their architectural works.
When I thought of the defence in ancient times, a shield shape came to my mind: a three-cornered, three-dimensional shape with rounded edges. While trying to harmonise this shape with the amphitheatre, by combining three right-sided triangles, I obtained a triangular three-dimensional unit with a triangular space in the middle and paraboloid sides, in other words, a shield with a hole in the middle. This shape was exactly what I wanted for the amphitheatre: it had the necessary slope and could provide the theatre echo. But I had a hard time integrating the shape into the castle, because it didn’t offer a flat area for people to use and it didn’t integrate with the castle. I started to integrate the shape into the castle and into human use: I made the paraboloid sides flat and the shape became a triangular prism with the top cut off. All the sides of this prism were equal, so that I could use it both separately and in combination for different purposes in the castle, for example: separately for windows, theatre and seating areas, and in combination for roofs. I also designed the floors of these spaces by rotating the squares, which are the combination of two isosceles triangles, ninety degrees.
I made my unit part of the bastion signs by using concave and convex windows: concave collects light, convex reflects it. I used concave windows for lighting in the bastion signs where circulation is important, and convex windows for sound isolation and semi-darkness in the zodiac sign which is the sound museum. -In addition, the sound museum includes a digital visual explaining the importance of the use of sound in theatre and an audio narration using the inner echo of the sign.-
In the amphitheatre, I designed the inside of the bastion as the backstage and the top part as the stage, and the inside and bottom of the units I placed on the sides of the bastion as the audience area. By adding larger units to the east and west ends of the square floor, I aimed to protect the area from light at sunrise and sunset; I also defined the west end as a viewing and seating area with a view of erciyes and the east end as a passageway.
The floor of the café part is the same as the theatre and has seating areas, the inside of the bastion is used as a kitchen and the bastion spaces are used as service areas, and the units on the edge of the floor are used as private seating areas compared to those on the floor. The roof of the café consists of units and is concave or convex according to the east and west directions.
In addition to these, there are two other square floors. Some parts of them are inside the castle and some of them are outside the castle, and complete each other in the frame. I used a roof made of units again on the outside part of these part.Finally; I created a single entrance to experience the entire area of the castle and adjusted the circulation accordingly. I tried to balance the density so that most of the circulation is inside the castle and most of the usage areas are outside the castle. 
