+sub want ($) {
+ my ($colournum) = @_;
+ my $knife = $nknives-1 - ($colournum-1) % $nknives;
+ return 0 unless $knife == $wknife;
+ my $part = $part_order[ floor(($colournum-1) / $nknives) ];
+ die "huh colour $colournum?" unless defined $part;
+ return 0 unless $part =~ m/[$wparts]/o;
+ print STDERR "$0: including colour $colournum ($knife $part)\n";
+ return 1;