diff --git a/docs/README_sequoia.md b/docs/README_sequoia.md
index 389653e..b308104 100644
--- a/docs/README_sequoia.md
+++ b/docs/README_sequoia.md
@@ -37,7 +37,7 @@ Version:  30-jul-2024
 	SRC_OBSNUM.wt3.fits         weight map v3 - RMS in line free region
 
 	SRC_OBSNUM.wtn.fits         ...coverage map (normalized) *BAD BEAM*
-	SRC_OBSNUM.wtr.fits         ratio of wt3/wt3
+	SRC_OBSNUM.wtr.fits         ratio of wt3/wt2
 	SRC_OBSNUM.wtr3.fits        ...
 	SRC_OBSNUM.wtr4.fits        RMS expected from radiometer equation (weighted average of Tsys/sqrt(df.dt))
 	
diff --git a/examples/simple_plot.py b/examples/simple_plot.py
index d60f3cf..7ed8b9c 100755
--- a/examples/simple_plot.py
+++ b/examples/simple_plot.py
@@ -1,45 +1,94 @@
 #! /usr/bin/env python
 #
-#   a simple matplotlib plot - testing for pipelines
+#   a simple matplotlib plot:  testing for MPL capabilities
 #
 #   setting the backend:
 #     1.  rcParams["backend"] parameter in your matplotlibrc file
 #     2.  The MPLBACKEND environment variable
 #     3.  The function matplotlib.use()
 #
-_version = "3-sep-2023"
+_version = "10-sep-2023"
+
+_help = """Usage: simple_plot.py [options]
+
+-p --plotfile PLOTFILE  Plot filename, extension is important. Optional.
+                        It none given, output should appear on screen.
+-b --backend BACKEND    Optional MPLBACKEND to use
+-s --show               Show available backends
+-d --debug              More debugging output?
+-h --help               This help
+-v --version            Script version
+
+This script allows you to easily test for matplotlib's
+capabilities in terms of picking interactive plotting
+vs. creating a plotfile, and selecting a backend
+if the default is not sufficient.
+
+By default the script should bring up an interactive plot
+and report in the title what backend was used.
+
+One can also set a default backend via an environment variable
+      export MPLBACKEND=agg
+or your matplotlibrc file (location varies per platform).
+Use --debug to see which one you should use.
+
+
+"""
 
 import os
 import sys
 import numpy as np
+from docopt import docopt
 
-if len(sys.argv) > 1:
-    _mode = int(sys.argv[1])
-    plotfile = 'simple_plot.png'
-else:
-    _mode = 0
-    plotfile = None
+# 1. Grab the command line arguments
+av = docopt(_help, options_first=True, version=_version)
+_debug = av['--debug']
+if _debug:
+    print(av)
+
+plotfile = av['--plotfile']
+backend = av['--backend']
+_mode = -1
+    
 
+# 2. MATPLOTLIB settings
 import matplotlib
-if 'MPLBACKEND' in os.environ:
-    print('$MPLBACKEND :',os.environ['MPLBACKEND'])
-    matplotlib.use(os.environ['MPLBACKEND'])          # isn't this redundant?
-else:
-    print("no $MPLBACKEND used")
-    if _mode == 0:
-        matplotlib.use('qt5agg')
-    else:
-        matplotlib.use('agg')
-        
+if av['--show']:
+    gui_env = [i for i in matplotlib.rcsetup.interactive_bk]
+    non_gui_backends = matplotlib.rcsetup.non_interactive_bk
+    print ("Non Gui backends are:", non_gui_backends)
+    print ("Gui backends I will test for", gui_env)
+    sys.exit(0)
+
+if plotfile is not None:
+    matplotlib.use('agg')     # use common plotfile capable backend
+if backend is not None:
+    matplotlib.use(backend)   # unless forced otherwise with --backend
+    
 import matplotlib.pyplot as plt
-print('mpl backend :',matplotlib.get_backend())
+
+if _debug:
+    print("Your matplotlibrc file:",matplotlib.matplotlib_fname())
+    if 'MPLBACKEND' in os.environ:
+        print('$MPLBACKEND :',os.environ['MPLBACKEND'])
+    else:
+        print("no $MPLBACKEND used")
         
+backend = matplotlib.get_backend()
+if _debug:
+    print('mpl backend :',backend)
+
+    
+# 3. Compute and plot        
 x = np.arange(0,2,0.1)
 y = np.sqrt(x)
 
 plt.figure()
 plt.plot(x,y, label="test");
 plt.legend()
+msg = f"plotfile={plotfile} mode={_mode} backend={backend}"
+plt.title(msg)
+
 if plotfile == None:
     plt.show()
 else: