How to use ranges?

[Doolan via Digitalmars-d-learn]

On Sunday, 23 August 2015 at 10:38:53 UTC, Rikki Cattermole wrote:
> On 8/23/2015 10:17 PM, Doolan wrote:
> Have a read of: 
> https://github.com/rikkimax/twp-d/blob/master/manuscript/content/idioms/ranges.md
>
> Let me know what you think :)

I think I'm a little more confused than before... this says there 
are two kinds of ranges and I thought there were five??