Source: quiver_demo.f90
See source and outputs below.
quiver_demo.f90 - Source codeoutput/example/fortran/quiver_demo/make example ARGS="quiver_demo"

ASCII output:
Quiver Plot Demo - Circular Flow
+--------------------------------------------------------------------------------+
| 1.0 |
| * |
| |
| |
| 0.8 \ ^ |
| |
| * |
| |
| |
| 0.6 |
| * |
| |
| |
| 0.4 |
| * < \ |
| |
| |
| |
| 0.2 |
| |
| |
| |
| * * * * * * |
|0.0 0.2 0.4 0.6 0.8 1.0 |
+--------------------------------------------------------------------------------+
X
Y

ASCII output:
Quiver Plot Demo - Smaller Arrows
+--------------------------------------------------------------------------------+
| 1.0 |
| * |
| |
| |
| 0.8 \ ^ |
| |
| * |
| |
| |
| 0.6 |
| * |
| |
| |
| 0.4 |
| * < \ |
| |
| |
| |
| 0.2 |
| |
| |
| |
| * * * * * * |
|0.0 0.2 0.4 0.6 0.8 1.0 |
+--------------------------------------------------------------------------------+
X
Y