Source: quiver_demo.f90
Quiver plots for discrete vector fields with scaled arrows and backend outputs.
quiver_demo.f90 - Source codeoutput/example/fortran/quiver_demo/make example ARGS="quiver_demo"

ASCII output:
Quiver Plot Demo - Circular Flow
+--------------------------------------------------------------------------------+
| 2.0 |
| | |
| | |
| | / < < < < < < < < \ |
| 1.5 |
| | / / < < < < < < \ \ |
| | |
| 1.0 |
| | / / / < < < < \ \ \ |
| | |
| | |
| 0.5/ / / / < < \ \ \ \ |
| | |
| | |
| 0.0v v v / / \ \ ^ ^ ^ |
| | |
| | v v v \ \ / / ^ ^ ^ |
| -0.5 |
| | |
| | \ \ \ \ > > / / / / |
| | |
| -1.0 |
| | \ \ \ > > > > / / / |
| | |
| -1.5 |
| | \ \ > > > > > > / / |
| | |
| | \ > > > > > > > > / |
| +--+-------+--------+--------+--------+--------+--------+--------+-------+---- |
| -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 |
+--------------------------------------------------------------------------------+
X
Y

ASCII output:
Quiver Plot Demo - Smaller Arrows
+--------------------------------------------------------------------------------+
| 2.0 |
| | |
| | |
| | / < < < < < < < < \ |
| 1.5 |
| | / / < < < < < < \ \ |
| | |
| 1.0 |
| | / / / < < < < \ \ \ |
| | |
| | |
| 0.5/ / / / < < \ \ \ \ |
| | |
| | |
| 0.0v v v ^ ^ ^ |
| | |
| | v v v ^ ^ ^ |
| -0.5 |
| | |
| | \ \ \ \ > > / / / / |
| | |
| -1.0 |
| | \ \ \ > > > > / / / |
| | |
| -1.5 |
| | \ \ > > > > > > / / |
| | |
| | \ > > > > > > > > / |
| +--+-------+--------+--------+--------+--------+--------+--------+-------+---- |
| -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 |
+--------------------------------------------------------------------------------+
X
Y