Why Floyd Obsessed Over This Detail of Its Ikea-Inspired BookshelfEasy of use and strength was key to creating a product that would last.

Even if you don't know it, youknowIkea's Billy bookcase. The Swedish retailer's simple 1979designhas sold more than 60 million units -- there's nearly one for every 100 people in the world. "But [many] end up in the trash," said Kyle Hoff, cofounder and CEO of Detroitfurnitureupstart Floyd.

Hoff and his team wanted to make a shelving unit with thesimplicityof the ubiquitous Billy but one that felt more lasting and less disposable. That meant it had to be sturdy but also freestanding, elegant, and endlessly modular -- a difficult combination. Floyd went through 40 iterations of the connection system that attaches the steel shelves to the wooden support stands. One version had a slim profile but couldn't hold enough weight. Another attempt was strong but required four fasteners per shelf. "If you lose one of those pieces, it's going to be a pain to disassemble and reassemble it," he said.