There's four main tombs in the garden, (well, one, Bara Gumbad [big dome] below, is really a big mosque with no sign of graves) ... these are the two in the middle.
Interior of mosque next to Bara Gumbad
Detail of arabesque calligraphy
Delhi is a fascinating city, really several different cities that have existed in this area from antiquity. A significant bit of its history was under Muslim rulers, and the architectural impact of a millenium or so of Islamic rule is everywhere. So much to explore!!