How (or why) does this bash script snippet work?

[Dean S. Messing]

On 13 Jan 2012 at 13:55:27, Cameron Simpson wrote:
<snip>
> The:
> 
>   <foo command [args...]
> 
> form is handy for programmatically constructed pipelines, too.

Sorry, I don't understand "programmatically constructed pipelines".
Would you elaborate?  Thanks