  We introduce a computational origami problem which we call the segment
folding problem: given a set of $n$ line-segments in the plane the aim is to
make creases along all segments in the minimum number of folding steps. Note
that a folding might alter the relative position between the segments, and a
segment could split into two. We show that it is NP-hard to determine whether
$n$ line segments can be folded in $n$ simple folding operations.
