UNFOLD []
UNFOLD [ ]
UNFOLD [ 'A' ]
UNFOLD [ F 'A' ]
UNFOLD [ F [ 'A' ]
UNFOLD [ F [ 'A' [ F ]
UNFOLD [ F [ 'A' [ F ] ]
UNFOLD [ F [ 'A' [ F ] ] 'B'
UNFOLD [ F [ 'A' [ F ] ] [ 'B' [ T ]
UNFOLD [ F [ 'A' [ F ] ] [ 'B' [ T ] ]
UNFOLD [ F [ 'A' [ F ] ] [ 'B' [ T ] ] ]
PRINT
