The tower's most remarkable feature is invisible until you count its sides. From a distance, it appears cylindrical. Up close, the exterior resolves into a polygon with 24 angles, a geometric choice that engineers believe distributes seismic force more evenly than a simple circle. Iran sits atop one of the world's most active tectonic zones, and the fact that this structure has survived since the 12th century while its dome did not speaks to the polygon's structural advantage. The brickwork itself is quintessentially Seljuk: precise, geometric, and decorated in patterns that turn functional masonry into ornament. Kufic inscriptions once ringed the top of the tower, though later restorations obscured much of the original calligraphy.

The tower may have served a purpose beyond the funerary. According to some accounts, fires were lit at the top on foggy nights to guide Silk Road caravans approaching Rey from Khorasan. The city of Rey was one of the great stops along the ancient trade route, a metropolis that rivaled Baghdad in its medieval prime. Travelers crossing the Iranian plateau would have needed landmarks, and a 20-meter tower with a flame at its summit would have been visible for miles across the flat approaches to the city. Some researchers also argue that the tower functioned as a kind of sundial, its 24 facets casting shadows that shifted with the hours, allowing the people of Rey to track the time of day by observing which face caught the sunlight.

The burial question refuses to resolve itself. The historical text Mahmalottavarikh states plainly that Sultan Tughril died in Rey and was buried there. The Turkish historian Faregh Sumer agreed. But the tower has also been attributed to Khalil Sultan, grandson of Timur and a Timurid ruler who lived in the 15th century, three hundred years after the tower's construction. Hassan Karimiyan, in his book on ancient Rey, notes that some scholars link the monument to Fakhr Deilami instead. Mohammad Mohit Tabatabai went further, attributing the building to Ibrahim Khawas. Tabatabai himself was buried beside the tower in 1992, adding one more layer to the site's accumulation of the dead and their stories.

The tower's survival has required intervention more than once. In 1884, Naser al-Din Shah Qajar ordered repairs to the crumbling upper sections. His chancellor, Amin al-Sultan, oversaw the work, which included installing marble slabs at the entrance. The restoration saved the structure but destroyed what remained of the Kufic inscriptions. After the 1978 revolution, the tower was abandoned and left to deteriorate. Serious reconstruction did not resume until 1998, continuing through the winter of 2000. Today, District 20 of Tehran Municipality is developing the surrounding two hectares into a cultural center with a library, museum, and restaurant. The tower that may have guided Silk Road travelers is finding a new role as the anchor of a neighborhood still searching for its identity on the sprawling southern edge of Tehran.