A number of fixes to improve the example:

• We should always aim for reduction in code duplication using globals wherever possible
• I've removed the tm_dynamic because there's no need to be looping over a list with a single entry, it only makes the example harder to follow
• I've prefixed all generated files with _, since this is a standard practice we use to ensure it's easy to distinguish between generated and non-generated terraform
• I've changed the before in VPC to be an after in EC2. Though they're logically equal, it's more normal to want to see the stack dependencies in the stack itself.
• I've removed the relative paths in the remote state and the after and replaced them with a stack-id and tags respectively (after doesn't support stack ids yet). Relative paths are fragile and make it much more difficult to reorganise code. I think it's best if we try to make this repo follow best practices even for simple examples.