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diff --git a/contrib/chem/examples/122/ch4t_polycyclic.chem b/contrib/chem/examples/122/ch4t_polycyclic.chem
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+ch4t_polycyclic.chem:
+.br
+.cstart
+
+# Example file for 'chem':
+
+# This originates from Computing Science Technical Report No. 122
+#   CHEM - A Program for Typesetting Chemical Diagrams: User Manual
+#   by Jon L. Bentley, Lynn W. Jelinski, Brian W. Kernighan
+#   <http://cm.bell-labs.com/cm/cs/cstr/122.ps.gz>.
+
+# Copyright (C) 2006-2020 Free Software Foundation, Inc.
+
+# This file is part of 'chem', which is part of 'groff'.
+
+# 'groff' is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License (GPL) version 2 as
+# published by the Free Software Foundation.
+
+# 'groff' is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# The GPL2 license text is available in the internet at
+# <http://www.gnu.org/licenses/gpl-2.0.html>.
+
+########################################################################
+
+R1: benzene pointing right
+    bond 30 from R1.V6 ; Br
+R2: benzene pointing right with .V5 at R1.V1
+R3: benzene pointing right with .V1 at R2.V3
+    bond 150 from R3.V2 ; CO2H
+R4: benzene pointing right with .V1 at R1.V3
+# next line names bond B1 so we can refer to its end
+B1: bond left from R4.V4
+    ring6 put N at 4 double 2,3 4,5 6,1 with .V3 at B1.end
+B2: bond right from R2.V1
+R5: benzene with .V5 at B2.end
+    ring6 put N at 4 double 1,2 3,4 with .V5 at R5.V3
+
+# Local Variables:
+# mode: Nroff
+# End:
+.cend