# [R], <s>270</s> <s>265</s> <s>252</s> <s>243</s> <s>232</s> <s>227</s> 225 bytes

*I finally managed to remove 2 more characters to bring the total to a number that can be represented in triangular form (as shown here). Code should be formatted conventionally to be run (as in the example on TIO); the '•' represents a newline (```\n```) character.* 

<!-- language-all: lang-r -->

                  f
                 unc
                tion(
               s,`~`=c
              bind,m=ma
             trix){n=nch
            ar(s)+1;p=m(,
           n^2,2);while(T<
          n){a=4*F;p[T+0:a,
         ]=c(F:-F,(-F:F)[-1]
        )~0:a-2*F;p[T+a+-2:a+
       3,]=(F=F+1)~(b=2*F-1):-
      b;T=T+2*a+4};m=m(" ",n,n)
     ;m[p[2:n-1,]+b+1]=el(strspl
	it(s,''));apply(m,1,cat,"•")}

[Try it online!][TIO-kezbft61]

[R]: https://www.r-project.org/
[TIO-kezbft61]: https://tio.run/##NY/LboMwEEX3/gqLLrBjUxWaFaq3fAE7RBUDTnBrxtQ2eTRKfp06UrMb6Zy5utetwWkJB6PEul@gD9oC8Xx334m@0zDwSUwyKmd6BQH9KB3xlOVoFhPh8FnwgqLTqI0i9QfQqxTbTYXmpmZvpeSt6ElVZhUnWVVWtMnylt4jyIp/SbKsKCV7jyapRMVyeiediDTLaZl1qBY1KzaSbW8o9iAJTjhwoGhq5qYoIct5yzqWt0IZ4oPzs9Ehtk9TSpGcZ3MhE895LwNPUEJv6wsGGxQOowz4uRs/Z@NReuxUWBzgozTLv6f94wmDUoMaOPYW@2CdGrB@aDGkixkpLMakeFROoccpnukkCaP6WXT/3Tl7gr09fy3T7O1RuQiM/L0M9vCa0PUP "R – Try It Online"

Note that this approach has been comprehensively outgolfed by [att's approach](https://codegolf.stackexchange.com/questions/210454/spiralize-a-word-triangularly/210543#210543), although as consolation neither that nor any of the other current answers can be represented as a triangle...

Works by constructing the coordinates for each letter, then using this to put the letters into an empty matrix.

Commented:
```
triangle=
function(s){n=nchar(s)			# n is the number of letters
s=el(strsplit(s,''))			# first split the string into individual letters
p=matrix(,2,n^2)				# initialize p as a 2-row matrix to hold the coordinates
								# (with plenty of columns so that we've enough to go all 
								# the way round the outermost triangle)
								# now, F is the current loop, starting at 0
while(T<=n){					# T is the current letter index
a=4*F+1							# a=the size of the 'arch' (number of letters going up & over)
p[,T+1:a-1]=					# set the coordinates for the arch letters...
  rbind(						# ...(rbind combines rows for y & x coordinates)...
    c(F:-F,(-F:F)[-1]),			# ...to y = F..-F, and then -F+1..F (so: up & then down again)
    1:a-2*F-1)					# ...and x = across the arch from -2*F to +2*F
a=a+2							# a=now the width of the base = size of arch + 2
p[,T+a+1:a-3]=					# now set the coordinates of the base letters...
  rbind(						#
    F+1,						# ... base y = row F+1
    (b=2*F+1):-b)				# ... and x = goes (backwards) from 2*F+1..-2*F-1
T=T+2*a-2						# update the current letter index
F=F+1}							# increment the loop
p=p[,1:n]						# delete any excess coordinates
p=p-min(p)+1					# re-zero the coordinates to remove negatives
m=matrix(" ",b<-max(p),b)		# create a new matrix filled with " "
m[t(p)]=s						# and fill it with the letters at the right positions
n=apply(m,1,cat,"				# finally, print each row
")}
```