diff --git a/cameo/fped2stl.pl b/cameo/fped2stl.pl
index 51204f4..63120ba 100755
--- a/cameo/fped2stl.pl
+++ b/cameo/fped2stl.pl
@@ -16,7 +16,7 @@ use POSIX;
 
 sub usage
 {
-	print STDERR "usage: $0 prefix [file ...]\n\n";
+	print STDERR "usage: $0 [-x] [-y] prefix [file ...]\n\n";
 	exit(1);
 }
 
@@ -59,7 +59,18 @@ print STDERR "$name $z ...\n";
 }
 
 
-&usage if $ARGV[0] =~ /^-[^0-9]/;
+while ($ARGV[0] =~ /^-/) {
+	if ($ARGV[0] == "-x") {
+		$flip_x = 1;
+	} elsif ($ARGV[0] == "-y") {
+		$flip_y = 1;
+	} elsif ($ARGV[0] =~ /^-[^0-9]/) {
+		last;
+	} else {
+		&usage;
+	}
+	shift;
+}
 
 $pfx = shift @ARGV;
 &usage unless defined $pfx;
@@ -77,6 +88,28 @@ while (<>) {
 	next if $skip;
 	next if /^#/;
 	$s{$z} .= $_;
+	if (/^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/) {
+		$xmin = $1 if $1 < $xmin || !defined $xmin;
+		$xmax = $1 if $1 > $xmax || !defined $xmax;
+		$ymin = $2 if $2 < $ymin || !defined $ymin;
+		$ymax = $2 if $2 > $ymax || !defined $ymax;
+	}
+}
+
+for $z (keys %s) {
+	undef $t;
+	for $s (split(/\n/, $s{$z})) {
+		if ($s =~ /^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/) {
+			$s = (($xmax+$xmin)/2-$1)." $2" if $flip_y;
+
+			# re-scan, so that we can flip on both axes
+			die unless
+			    $s =~ /^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/;
+			$s = "$1 ".(($ymax+$ymin)/2-$2) if $flip_x;
+		}
+		$t .= "$s\n";
+	}
+	$s{$z} = $t;
 }
 
 undef $last;