Many of today’s most famous inventions were created in response to common everyday problems. If you’re looking for inspiration that will prompt you to launch a startup that helps address a problem, check out these inventors’ stories.

1. George de Mestral, Velcro Inventor

During a hunting trip, George de Mestral noticed that he and his dog were coated in burrs that had come from plants along the French countryside. A longtime science enthusiast, de Mestral put the burrs under a microscope to see what made them so capable of sticking, and found that they were comprised of tiny hooks that allowed them to cling to fibers.

He knew that there was a need to solve a closure problem that couldn’t be addressed with existing fasteners, such as zippers and buttons, and decided to see whether he could create a product that allowed hooks and loops to stick together, mimicking the burrs’ behavior.

Giving his company the name “Velcro” to combine the words “velvet” and “crochet,” de Mestral successfully turned a problem into a solution, and his products have endured for many years following his burr problem back in 1941.

2. Martin Cooper, Mobile Phone Pioneer

Although AT&T’s Bell Labs pioneered the idea of moving calls from one cell to another without dropping the call, the company was initially using the technology to develop car phones. At rival Motorola, researcher Martin Cooper worked to bring that technology to a mobile format, which birthed the idea of the portable cell phone.

The problem he was trying to solve is clear to anyone who was around when only landlines were available. “For 100 years, people wanting to talk on the phone have been constrained by being tied to their desks or in their homes with a wire,” he later told CNN.

After three months working on the prototype, Cooper made the first public cell phone call in 1973 on the streets of New York City. That phone, which weighed about two and a half pounds and featured battery life of 30 minutes of talk time, eventually evolved to the slim smartphones we have today.

3. George Eastman, Who Invented the Portable Camera

Today, nearly everyone has a portable camera with them at all times, thanks to the magic of the smartphone. But in the 1800s, most people didn’t have access to modern photography equipment, because it was expensive and cumbersome.

In 1878, George Eastman was working as a bookkeeper at Rochester Savings Bank in upstate New York. Planning to travel abroad, Eastman hoped to take photos of his trip and bought photography equipment, but found it to be too heavy and bulky to take along. Upon returning from his travels, Eastman began working on a way for people to actually take cameras with them wherever they might go.

He was successful enough at the venture to quit his job in 1880, and by 1900 he had launched the Brownie camera, which cost just a dollar and allowed everyone from servicemen, children and families to take photos no matter where they went.

Had Eastman not been interested in documenting his trip abroad, he may never have noticed the problem of cumbersome photography equipment, which he ultimately solved.