It’s been four months since the tragic death of a Merced teenager. Sixteen-year-old Riley Hanson’s family is still coping with her loss, and they’re trying to keep her memory alive.

Now Riley’s legacy is being spread globally through an object you may not expect.

That beam of a grin would become her legacy. By the time Riley was 16, she was a straight A student as a senior at El Capitan High School in Merced.

She had a passion for color guard, loved the arts and stood up for equality.

“She was constantly advocating for the little guy. She felt that the underserved communities like the LGBT community specifically were just not being properly represented in our country and around just in general,” said Matt Escobar, Riley’s stepdad.

On Sept. 23, 2018, Riley was spending her weekend in Sacramento. Her stepdad Matt says she texted him about the gift she bought her mother.

Thirty minutes later, a car crash involving multiple vehicles killed Riley as she sat in the passenger seat. She would have turned 17 the next month.

“Every day we just wake up with that feeling of just panic that our child is not home. Our kid’s not with us,” Matt said.

Since her death, the struggle has taken a toll on Riley’s mother.

“Disheartening and just sad to see that woman who has been so strong for us just brought to her knees,” Matt said.

He adds, “You wanna make sure that whatever size rock that you have, that you make as big of a heart as you possibly can.”

Riverbed rocks – each about the size of the palm of your hand carrying a message in Riley’s honor.

The core of it all – a yellow heart with a smiley face inside of it.

“Yellow really embraces her personality and just that cute little heart smile just really like represents what she is. And it’s just crazy how just one look at it and it instantly reminds me of her,” said Katie Escobar, Riley’s stepsister.

Of course the hashtag says #SmileyRiley. The rock is finished with a loving note – exactly how Riley would want it.

“This makes us feel as if she’s here. She’s present with us,” Matt said.

How did this art project become so therapeutic?

Shortly after Riley’s funeral, Matt’s brother Joe began coloring rocks in her honor. One became 10 – dozens became hundreds.

Then Joe had 1,000 Smiley Riley rocks, but what next?

Matt and his brother’s idea evolved. They’d keep Riley alive by placing the rocks at spots that meant something to her. El Capitan High where she spent hours on hours practicing color guard – Merced College where she studied statistics. Riley wanted to be a math teacher one day. Mercy Medical Center where Riley and her siblings usually met with their mother – a nurse.

“So this whole area – this little shopping center is called the Promenade. This is where – one of their favorite hangouts,” Matt said.

Smiley Riley’s rocks are scattered across Merced. People who never met Riley find them, and the hashtag leads to her story.

For the first time, Matt left a rock at the park where Riley grew up playing.

But her presence is traveling to destinations she only dreamed of.

Riley’s now on Broadway in New York City – in the snow of Green Bay, Wisconsin. She’s down south in Dallas, Texas.

On an interactive Google Map, so many towns and cities across America are marked in yellow.

After someone sends a photo of the rock’s whereabouts to her family, Riley’s international now. From Europe to Africa.

“It’s a universal feeling of happiness. Everyone needs it no matter where you are in the world. That was Riley. That’s who she was. No matter what day, rain or shine, she was gonna make you smile at some point. And she was gonna do whatever she could in her power to brighten up your day.”

RELATED: Learn more about Riley’s story here.

Ask Julia Aitchison in Capetown, South Africa. She was diagnosed with breast cancer last August. Since then she’s fought the toughest battle of her life – enduring hours of chemotherapy.

“Constant nausea – I feel weak and vulnerable and just – I feel like I’m 95 years old,” Julia said.

Julia and her daughter found the Smiley Riley legacy page on Facebook and decided to contribute their own rocks, placing them around South Africa. The smile spreading around the world reminds Julia what’s most important to her.

“I can see that in my daughter and through seeing videos and pictures of Riley and having my daughter with me and going through chemo, it’s made me appreciate my daughter more and life in general,” Julia said.

Matt said, “I think one of the most important lessons that Riley taught me that I try to practice every day is patience and love and acceptance for everybody – absolutely anybody and everybody. Riley was not impressed with money, fancy stuff or items. She was impressed with your soul, who you were.”

If you loved Riley, you can find her in your favorite memories, precious photos and funny videos.

But for those who didn’t experience those moments, they can stumble upon a rock with a yellow heart on it with a message behind it. And just maybe it was Riley who found them.

Matt said, “It makes us feel like Riley was able to accomplish some of these goals that she set out to do and touch people and impact people the way that she would have.”