Example of how to do nested loops. 15 minutes of code :)

examples/playbooks/loop_nested.yml

+---
+# this is a trivial example of how to do a nested loop.
+
+- hosts: all
+  tasks:
+    - shell: echo 'nested test a=${item.0} b=${item.1} c=${item.2}'
+      with_nested:
+        - [ 'red', 'blue', 'green' ]
+        - [ 1, 2, 3 ]
+        - [ 'up', 'down', 'strange']