Lal Kitab is the undisputed master of physical and Vastu *Nishaniyas* (signs).
Rahu represents height, expansion, and tall structures. The 6th house represents the physical body and the immediate surroundings.
When Rahu sits in the 6th house, it manifests in two undeniable ways: 1. Physical: The person will be noticeably taller ("kuch lamba") than the rest of their family members. 2. Vastu: There will be a tall electric pole, a dead tree, or a prominent pillar ("khamba") standing right outside their house.
If you see these two signs, you don't even need to look at the birth chart to know Rahu is in the 6th!