Fold a string into a triangle Given a string whose length is divisible by 4, make a triangle as demonstrate below.

If the string is abcdefghijkl, then the triangle would be:

   a
  b l
 c   k
defghij


If the string is iamastringwithalengthdivisiblebyfour, then the triangle would be:

         i
        a r
       m   u
      a     o
     s       f
    t         y
   r           b
  i             e
 n               l
gwithalengthdivisib


If the string is thisrepresentationisnotatriangle, then the triangle would be:

        t
       h e
      i   l
     s     g
    r       n
   e         a
  p           i
 r             r
esentationisnotat


Notes


The string will only consist of characters from a to z.
Leading/Trailing whitespaces and newlines are allowed as long as the shape is not broken.
A list of strings as output is allowed.


This is code-golf. Shortest answer in bytes wins. Standard loopholes apply.
Charcoal, 25 22 21 bytes

≔÷Ｌθ⁴λ↙…θλ→✂θλ±λ↖✂θ±λ


Try it online! Link is to verbose version of code. Simply slices the string into three parts and prints them in the appropriate directions. Edit: Saved 3 bytes by using integer division and slicing. Saved a further byte by using CycleChop instead of Slice for the head of the string. Edit: Charcoal now supports drawing arbitrary text along the edge of a polygon, simplifying the code to 12 bytes:

ＧＨ↙→→↖⊕÷Ｌθ⁴θ


Try it online! Link is to verbose version of code.