Gillis Lundgren, an industrial designer who helped make Ikea the largest furniture retailer in the world with his no-frills designs, most notably the Billy bookcase that millions of frugal book collectors have used to build their home libraries, has died at 86.

Kajsa Johansson, an Ikea spokeswoman, confirmed his death, describing him as “a man full of ideas that he quickly turned into practical products,” but gave no other details. Quartz magazine reported in an online obituary that he died Feb. 25.

Founded in the Swedish countryside in 1943, Ikea grew from an all-purpose, low-cost retailer for farmers into a corporate behemoth with 328 stores in 28 countries and a reported $35.7 billion in sales in fiscal 2015. Its founder, Ingvar Kamprad, who began his career as an enterprising teenager peddling mail-order nylon hosiery and udder balm, is today one of the richest men in business.

Lundgren joined Ikea in 1953 as the company’s fourth employee and advanced to become its first design manager. A draftsman with training in graphics, he designed hundreds of Ikea’s simple, portable furnishings and was credited with creating the company logo, an emblem whose blue and yellow colors were taken from the Swedish flag.

Ikea announces itself along roadways with the apparition of its mammoth warehouses, also blue and yellow, and in the mail with the arrival of its nearly warehouse-size catalogs. Every year, hundreds of millions of shoppers – new students and new graduates, new tenants and new homeowners, the newly married and the newly divorced – trek into Ikea stores in pursuit of the economical establishment of a household.

While few of those people are likely to know Lundgren’s name, all of them are or will soon become acquainted with perhaps his most significant contribution to the Ikea business model: “flat-pack” furniture.

Ikea was not the first company to employ the now-ubiquitous system, but Lundgren was credited with perfecting it for Ikea’s purposes. He said the idea came to him early in his career. Ikea had recently entered the furniture market, he recalled, and “storage space became an issue.”

“When I looked at how we might keep a large number of these tables at our low price,” he said, “I thought: ‘Why not take off the legs?’ “

Today, shoppers peruse fully assembled Ikea wares in showrooms and on the company’s website but take home (or order for delivery) boxes that contain the products in pieces, neatly stacked, to be assembled on arrival. The flat-pack system allows Ikea to save money by moving its products more efficiently and customers to save money, although not time, by providing the labor.

To instruct customers in assembly, Ikea prints wordless, illustrated manuals featuring cartoon-like figures at work. Those figures do not appear prone to the frustrations involving stripped screws or missing parts that have helped turn the Ikea clientele into a quasi-fraternity.

Lundgren was born in Lund, Sweden, in 1929. He studied at Malmo technical college and joined Ikea as a catalog manager.