@Matthew: Glad it helped!
@Kat: Whoops! Apparently fibia is a commonly made-up word :).
Thanks Aaron, glad it helped!
Click
After 25 years, thank you oh so very much.
"[…]like biologists who find a link between your fibia and clavicle."
What in the world is a fibia? Of all my years in sports medicine and direct research in human performance, I have never heard of a fibia. I am assuming you either meant tibia or fibula. Thanks for the laugh.
the ceiling is another tangent to the same dome can the ceiling play the two roles ?
@sayed: The ceiling and wall are very similar. If you flip the wall and ceiling, the tangent/cotangent are switched as well. This is the same as swapping an angle for its complement, so tan(a) = cot(90 - a).
Thank you so much for this Kalid! You are absolutely amazing!! 
It’s a real shame that maths isn’t taught this way at school. I am starting to enjoy maths so much more after reading your articles. Just in time, as I’m starting my computer science degree soon!