The tomb of the Sufi saint Khalil Allah (d. 1460/864 AH) is a two story octagon with a freestanding square domed tomb chamber within, entered through a large gateway with pointed arches. The outer octagonal curtain wall has arched recesses flanked by panels with diagonal squares, all outlined in black carved stone bands, and was likely meant to be covered in colored tilework. Inscriptions of Koranic verses dated 1450/853 AH adorn the doorway. The calligraphy on the basalt lintel of the entrance is of exceptional quality.
Sources:
Johnson, Gordon, Mark Zebrowski, and George Michell. The new Cambridge history of India, 1, 7, 73. Cambridge: Cambridge Univ. Press, 1999.
Merklinger, Elizabeth Schotten. Sultanate architecture of pre-Mughal India, 133-134. New Delhi: Munshiram Manoharlal Publishers, 2005.