From e84b0f7afdcece65d767e2f1377e4836005bab80 Mon Sep 17 00:00:00 2001
From: Jonathan Neuhauser <jonathan.neuhauser@outlook.com>
Date: Sun, 16 Jan 2022 17:44:47 +0100
Subject: [PATCH] fix #408

---
 polyhedron_3d.py                                                | 2 +-
 ...hedron_3d__--show__edg__--obj__methane__--cw_wound__True.out | 2 ++
 tests/test_polyhedron_3d.py                                     | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)
 create mode 100644 tests/data/refs/polyhedron_3d__--show__edg__--obj__methane__--cw_wound__True.out

diff --git a/polyhedron_3d.py b/polyhedron_3d.py
index 68298e6c..f7281d65 100755
--- a/polyhedron_3d.py
+++ b/polyhedron_3d.py
@@ -224,7 +224,7 @@ class WavefrontObj(object):
         # we need at least 2 vertices to make an edge
         if len(vtxlist) > 1:
             # we can have more than one vertex per line - get adjacent pairs
-            self.edg.append(pairwise(vtxlist))
+            self.edg.extend(pairwise(vtxlist, start=False))
 
     def add_f(self, line):
         """Add face from parsed line"""
diff --git a/tests/data/refs/polyhedron_3d__--show__edg__--obj__methane__--cw_wound__True.out b/tests/data/refs/polyhedron_3d__--show__edg__--obj__methane__--cw_wound__True.out
new file mode 100644
index 00000000..9bd5bdef
--- /dev/null
+++ b/tests/data/refs/polyhedron_3d__--show__edg__--obj__methane__--cw_wound__True.out
@@ -0,0 +1,2 @@
+<!-- Created with Inkscape (http://www.inkscape.org/) --><svg xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:cc="http://creativecommons.org/ns#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" version="1.1" width="793.7007874" height="1122.519685">
+<ns0:namedview xmlns:ns0="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"/><svg:g xmlns:ns1="http://www.inkscape.org/namespaces/inkscape" ns1:label="methane:x0.00:x0.00:x0.00:x0.00:x0.00:x0.00"><svg:path style="fill:none;stroke:#000000;stroke-linecap:round;stroke-width:2" ns1:label="Edge1-2" d="M 0 -0 L 0 -0"/><svg:path style="fill:none;stroke:#000000;stroke-linecap:round;stroke-width:2" ns1:label="Edge1-3" d="M 0 -0 L -28.8675 50"/><svg:path style="fill:none;stroke:#000000;stroke-linecap:round;stroke-width:2" ns1:label="Edge1-4" d="M 0 -0 L -28.8675 -50"/><svg:path style="fill:none;stroke:#000000;stroke-linecap:round;stroke-width:2" ns1:label="Edge1-5" d="M 0 -0 L 57.735 -0"/></svg:g></svg>
\ No newline at end of file
diff --git a/tests/test_polyhedron_3d.py b/tests/test_polyhedron_3d.py
index f4f810e1..4c26ace0 100644
--- a/tests/test_polyhedron_3d.py
+++ b/tests/test_polyhedron_3d.py
@@ -12,6 +12,7 @@ class Poly3DBasicTest(ComparisonMixin, TestCase):
         ('--show=fce', '--obj=cube', '--r1_ax=z', '--r1_ang=45', '--z_sort=max', '--cw_wound=True'),
         ('--show=edg', '--obj=oct', '--r1_ax=z', '--r1_ang=45', '--th=4', '--cw_wound=True'),
         ('--show=vtx', '--obj=methane', '--cw_wound=True'),
+        ('--show=edg', '--obj=methane', '--cw_wound=True'),
         ('--show=fce', '--obj=from_file', '--spec_file=great_stel_dodec.obj', '--cw_wound=True'),
     ]
     compare_file = 'svg/empty.svg'
-- 
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