Works not on words, but 114 char:

@ARGV="ctriangle.txt";
sub n{print$"x(40-$r),@b,$/}
@a=map{split}<>;$,=$";while($r++<@a){@b=splice@a,0,$r;n}$r--,n
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"We are not alone"(FZ)
Update: Most of this is just an adaption of the other code in this nice thread, including the $". I like xterm's idea of map{split}<> very much I must say. But the '$,' was my own creativity....