A picture is a thousand words and Sir Wolf beat me once again on one of my favourite topics : Steck !!!!
A couple of things to remember
(1) 3 way ( T) Steck connectors an essential for any large steck designs
(2) 2 way connectors a must if building is over one steck in height
(3) Rare but they exist - 4 way connectors ( in light brown only) can prove very handy see my latest steck mediavl set up the front of the royals' quarters .
(4) Special connectors needed for joining round steck towers with walls - See Sir Wolf's picture.
(5) There is never enough Steck !