1 files changed, 48 insertions, 0 deletions
diff --git a/contrib/chem/examples/122/ch4g_BP.chem b/contrib/chem/examples/122/ch4g_BP.chem
new file mode 100644
index 0000000..9c6af4b
--- /dev/null
+++ b/contrib/chem/examples/122/ch4g_BP.chem
@@ -0,0 +1,48 @@
+ch4g_BP.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>.
+
+########################################################################
+
+# this is the isopropyl group
+    bond 120 ; BP       # BP is right end of this bond
+    bond -120 from BP
+    bond right from BP ; C
+    front bond up ; CH3
+    back bond down from C ; D
+    bond right from C ; BP
+# redefine BP to mean the center carbon of this t-butyl group
+    bond up from BP
+    bond right from BP
+    bond down from BP
+
+# Local Variables:
+# mode: Nroff
+# End:
+.cend