sub merge {
    my @allparts = @_;

    my @complete = @{shift(@allparts)};
    ALLPARTS: while(@allparts) {
        for(0 .. $#allparts) {
            my @thispart = @{$allparts[$_]};
            if($thispart[0] == $complete[$#complete]) {
                shift(@thispart); # remove part, so we don't double points
                @complete = (@complete,@thispart);
                splice(@allparts,$_,1);
                next ALLPARTS;
            }
            if($complete[0] == $thispart[$#thispart]) {
                shift(@complete); # remove part
                @complete = (@thispart,@complete);
                splice(@allparts,$_,1);
                next ALLPARTS;
            }
        }

        die "Found pieces that don't fit!\n".Dumper(@allparts);
    }
    return @complete;
}