Olle Bærtling (1911–81) was born in Halmstad, Sweden in 1911 and moved to Stockholm at a young age where he worked at a bank. In 1948, he started at André Lothe's painting school, where he did not stay long, however, as he and his teacher saw the lines in nature differently. He then transferred to Fernand Léger's painting school where he laid the foundation for his future creations. Bærtling would become the foremost representative of a strictly geometric art in Sweden. He painted his first "open form" paintings in the early 1950s. Before that he painted in an expressionist style, before his non-figurative painting began to take shape. Bærtling was a concretist, who deliberately sought to distance himself from the realistic. His exploration of the dynamics of the triangular shape and the ability of colors to reinforce the shape with their color fields creates an optical illusion. Bærtling's artwork puts us viewers to the test, as the art is based on our ability to see. Patience and an open mind are of great importance.

"The art of the open form can be likened to the immaterial power and grandeur of the sky, infinite space: it is organized light, strongly dynamic in infinity. The work is conceived and formed as an instrument; the abode of spiritual nature is the real work.”

The paintings are dominated by triangular fields with a black outline that meet with sharp angles, horizontal and vertical lines. Open shapes that give the impression of continuing beyond the borders of the image. An extension of the room, straight out into space. "Baertling's work extends beyond this into space, the outer contours of which he leaves our imagination to anticipate." He also translated the contours into sculptures. Where they assumed a floating character with their black lines against the sky. Olle Bærtling is the "master of the open form", an extension to infinity.