I always thought the isometric cover of series spines was an industry standard...

You know the one I'm talking about. Whenever I see an eBook series on sale in a single volume, the cover looks like this:

https://m.media-amazon.com/images/I/...L._SL1500_.jpg

I had always assumed that was an unspoken standard among the major publishers. But it turns out, no, it's all from a single publisher, and apparently I just happen to purchase like 70% of my books from Open Road Media!