diff --git a/lib/Slic3r/Fill/Concentric.pm b/lib/Slic3r/Fill/Concentric.pm
index a7d1c006..ef61eb80 100644
--- a/lib/Slic3r/Fill/Concentric.pm
+++ b/lib/Slic3r/Fill/Concentric.pm
@@ -29,7 +29,7 @@ sub fill_surface {
     
     # compensate the overlap which is good for rectilinear but harmful for concentric
     # where the perimeter/infill spacing should be equal to any other loop spacing
-    my @loops = my @last = @{offset($expolygon, -&Slic3r::INFILL_OVERLAP_OVER_SPACING * $min_spacing / 2)};
+    my @loops = my @last = @{offset(\@$expolygon, -&Slic3r::INFILL_OVERLAP_OVER_SPACING * $min_spacing / 2)};
     while (@last) {
         push @loops, @last = @{offset2(\@last, -1.5*$distance,  +0.5*$distance)};
     }
@@ -41,9 +41,9 @@ sub fill_surface {
     
     # order paths using a nearest neighbor search
     my @paths = ();
-    my $last_pos = [0,0];
+    my $last_pos = Slic3r::Point->new(0,0);
     foreach my $loop (@loops) {
-        push @paths, $loop->split_at_index($last_pos->nearest_point_index($loop));
+        push @paths, $loop->split_at_index($last_pos->nearest_point_index(\@$loop));
         $last_pos = $paths[-1][-1];
     }
     
diff --git a/t/fill.t b/t/fill.t
index 484217d0..4885275d 100644
--- a/t/fill.t
+++ b/t/fill.t
@@ -2,7 +2,7 @@ use Test::More;
 use strict;
 use warnings;
 
-plan tests => 33;
+plan tests => 34;
 
 BEGIN {
     use FindBin;
@@ -155,11 +155,11 @@ sub scale_points (@) { map [scale $_->[X], scale $_->[Y]], @_ }
         'chained path';
 }
 
-{
+for my $pattern (qw(hilbertcurve concentric)) {
     my $config = Slic3r::Config->new_from_defaults;
-    $config->set('fill_pattern', 'hilbertcurve');
+    $config->set('fill_pattern', $pattern);
     my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-    ok Slic3r::Test::gcode($print), 'successful hilbertcurve infill generation';
+    ok Slic3r::Test::gcode($print), "successful $pattern infill generation";
 }
 
 {