The language contains 3 different characters to represent the code: Space, Tab(\t), LF(\n).
Different combinations of characters form a series of operands that let this language be Turing-complete.
!S, T, L corresponds to space, tab and LF respectively
S S STSSTSSSL !push number +1001000('H') to stack
TL SS !print the character at the top of stack: 'H'
S S STTSSTSTL !push 'e'
TL SS !print 'e'
S S STTSTTSSL !push 'l'
S LS !duplicate the top element of the stack
S LS !stack: ['l','l','l']
TL SS !print 'l'
TL SS !print 'l'
S S STTSTTTTL !push 'o'
S LS !stack: ['o','o','l']
TL SS !print 'o'
S S STSTSTTTL !push 'W', stack: ['W','o','l']
TL SS !print 'W'
TL SS !print 'o'
S S STTTSSTSL !push 'r', stack: ['r','l']
TL SS !print 'r'
TL SS !print 'l'
S S STTSSTSSL !push 'd'
TL SS !print 'd'
LLL !program ends