Bold. Curvy. Beautiful.

Nope, I'm not talking about a person. I'm talking about water bottles. S'well water bottles to be exact.

People can't get enough of the chic, fashionable bottles that keep their beverages hot or cold. They've actually become collectors' items. The average S'well consumer owns at least five. The secret? It's all about the bottle designs. The company partners with artists and fashion designers to create the bottle designs. These bottles are equal parts fashion and function. You could call S'well bottles highly Instagrammable. (Hashtag #swelladventures.)

When founder and CEO Sarah Kauss launched swell in 2010, she did it with $30,000 of her personal savings. With her eye for design and fashion-forward strategy, she turned that $30,000 into a goldmine. The company brought in $100 million in revenue last year. S'well has never taken outside funding.

And she's not stopping. Kauss has big plans to continue to grow S'well and achieve total beverage container domination. Kauss told Inc. last spring that she envisions this being a billion-dollar company.

This week, the company revealed some big news that gives a peek into how S'well plans to get there. After seven straight years of sticking to their tried-and-true water bottle product line, S'well is venturing out into new hydration waters. They're shaking things up, going "beyond the bottle" if you will. S'well tumblers and travel mugs have arrived. No matter where you want to enjoy a hot or cold beverage, there is now a fashionable S'well container for the occasion.

Here are just a few ways Kauss has designed this brand from the ground up -- and will continue to grow it for long-lasting success.

Create the right feeling

Spend a few minutes scrolling through the S'well website. A beautiful millennial-looking couple drinks wine out of S'well bottles while casually hanging on a picnic blanket with a glorious cheese plate. The website copy reference hot yoga and green smoothies.

Kinda feel like you now need to own your very own S'well to live your best life? That's intentional by design.

When compared to the other reusable options out there. Most of them are clunky and ugly. I own a sleek glass bottle with a mint green silicone cover. I frequently receive compliments. But it's so heavy that I often leave it at home.

The functionality of S'well bottles are not an afterthought. On the website, all the nitty gritty info about the product's design is there, too. The bottles are "non-leaching and non-toxic, 18/8 stainless steel." But that's not what draws people in.

You buy it because toting a S'well to yoga or your next garden party will make your life just that much fab.

Create get-it-while-it's-hot demand

S'well never introduces new colors. Instead, the company launches collections. The Forbidden Garden Collection features floral patterns. The Elements Collection features marble, granite and mother of pearl designs.

Every six months, S'well releases 30 new designs. Then they're gone, and without warning. If you don't swoop one up, you're out of luck. You might be able to find an old design on eBay, but you'll pay a price.

This has been a vital part of Kauss' growth strategy. For her most loyal customers, one S'well is never enough. "Our customers become collectors because we try to have the right trends, the right patterns," Kauss told Inc editor-at-large Kimberly Weisul. "We like to make something that's very covetable."

Give the people what they want

After seven successful years, it might seem surprising that it took S'well so long to expand their product line. But this, too, is by design. For the past several years, Kauss and her team have been listening to their consumers, gathering intel and brainstorming the next greatest hit.

They heard that people wanted containers with wider mouths for ice cubes. That they wanted containers to sip those green smoothies. When S'well was finally ready to introduce new products, they already knew which ones would resonate best with their die-hard customers. "Finally!!!" one fan posted on the S'well Instagram, "I've been waiting for this! I had to buy another brand and look forward to donating it now that I can get yours."