"Imagine if everything we made had a beneficial impact on the planet's resources," Bridgett Luther, founder of the Cradle to Cradle Products Innovation Institute, wrote in a prompt for its second design challenge. Sponsored by the Institute and Autodesk, the Cradle to Cradle Product Design Challenge seeks to inspire up-and-coming designers to create products for the circular economy -- highlighting safe materials that can be perpetually cycled.

The second iteration of the challenge attracted participants from 18 countries, including India, Canada, Portugal, the Netherlands and the U.S., who submitted closed-loop innovations for everything from the built environment to retail goods. It's not only a way to help emerging designers stand out, but also an ongoing tool for educators, coinciding with fall and spring semesters as an optional curriculum supplement.

Participants are required to take a free two-hour, online course about designing for the circular economy, made possible by a partnership with the Alcoa Foundation, prior to entering the challenge. So, even those who don't win will still walk away with an increased knowledge of cradle-to-cradle design.

"Designing for a world facing finite resources and a growing population requires enterprising and intrepid designers, and it's exciting to see these young designers rise to the challenge," said Lynelle Cameron, senior director of sustainability for Autodesk and CEO of the Autodesk Foundation, in a statement.

The ultimate goal of the bi-annual challenge, the Institute says, is to "eliminate the concept of 'waste.'" Such a reality may seem like a long way off, but it's the new year, so let's dream big here, people. And the four winning ideas, submitted by young designers from the U.S. and the Netherlands, are sure to make dreaming big a bit easier. Read on to be inspired.

Onward Bag

Winner: Best Student Project Gabriella Jacobsen, a student at Virginia Tech, designed the Onward Bag to address the issue of plastic bags as a major pollutant in oceans and waterways

Designed to be used as either a backpack or a briefcase, the Onward Bag is made from 60 to 70 recycled plastic bags, a yard of organic cotton canvas, canvas thread, and biodegradable dye. The user can easily cut a few stitches to fully separate the two fabrics, allowing the entire bag to be recycled and composted respectively.

Jacobsen even modeled the pattern used in the design after ocean waves. How cool is that?

BikeShare Helmet

Winner: Best Professional Project Barent Roth, a designer and educator from Brooklyn, New York, won top honors for his BikeShare Helmet, a simple unisex style bike helmet designed specifically to integrate with the growing bike-share community

The helmet is comprised of a recycled aluminum foam shell and sustainably-grown, FSC-certified cork liner to provide maximum protection with minimal bulk and weight, while ensuring all materials can be either recycled or composted at end-of-life.

Designed as a Product Service System, the helmet can be purchased as a recommended upgrade to existing annual bike-share memberships. Two-wheeled transport with a side of closed-loop innovation? Sign us up!

AtoB Seat

Winner: Best Use of Aluminum Aluminum is one of the most readily-recyclable materials out there. It can be cycled over and over again with no loss in quality. The aluminum recycling system has become so advanced that 100-percent recycled aluminum cans now sit on store shelves in North America.

Winning top brass in the challenge, Michiel Meurs of FromAtoB Public Design in Bunnik, Netherlands, and his team devised a new use for the material: the AtoB Seat. Designed for public transit trains, the seat is made from recycled aluminum, recycled PET and formaldehyde-free bamboo plywood. The parts are connected with specially-designed fasteners for easy disassembly, making it faster and more affordable to service and maintain the seats during their lifetime.

Some of the parts, such as the upholstered seat and back panels, have a shorter lifetime than others. By replacing and upgrading them, the total lifespan of the seat can be expanded -- reducing waste and cutting costs for public transit systems that may already be hurting for cash.

Sweeping the Nation with Change

Winner: Best Use of Autodesk Fusion 360 Okay, so a broom isn't exactly the most exciting household item we can think of, but imagine how many of these you throw away over years of cleaning your home. The handles can last for decades, but the bristles become gnarled and dirty (not exactly something you want to run across your floors), so you toss the whole thing in the trash -- making waste of still-usable materials.

It's a pretty simple concept, but it's one that challenge judges determined can keep heaps of material out of the landfill. And we're inclined to agree. Here's a rundown: The Rochester Institute of Technology chapter of Engineers for a Sustainable World developed a recyclable broom with a bristle head made of highly biodegradable (and low-cost) wheat straw. The head can be replaced independently of the broom’s other components, so users can easily remove and compost icky bristles without trashing the recycled aluminum handle.

The broom they named “Sweeping the Nation with Change” was assembled using Autodesk's Fusion 360 and looks pretty darn handy, even if you don't give a hoot about recycling (which, you know, you should).

Do you have a closed-loop design you'd like to share with the world? Sign up for the third Cradle to Cradle Product Design Challenge here. Submissions are due by May 1.

Images courtesy of the Cradle to Cradle Products Innovation Institute