Agnes Martin at Tate Modern, the grid, Saskatchewan

Geometry has nothing to do with it. It’s all about finding perfection and perfection can’t be found in something so rigid as geometry. You have to go elsewhere for that, in between the lines.                                                                                                                                  — Agnes Martin

"Agnes Martin’s lifelong dedication to simplicity of mind was perhaps made easier (it was certainly not impeded) by the faint trace of simple-mindedness in her nature. Had she not had about her a touch of the holy fool, the strange and specialised soul of a secular saint, her life and work would not have attained its compelling singularity. She famously said that the artist should paint with her back to the world. The world, meanwhile, was always ready to embrace her, and in the 1960s she was a successful member of the New York avant garde. But her centre of gravity lay way outside the bright metropolitan circle, and her renunciation of the urban scene, her turning away so decisively from social living, was only a matter of time in coming. Perhaps she had no choice but to follow her lodestar, but nothing should diminish her extraordinary courage in doing so. In 1967, with her reputation at its zenith, she lay down her brushes, gave away her painting materials, bought a pick-up truck and headed out West, telling a friend that she did not intend to speak to anyone for three years. After eighteen months, she came to rest on a remote mesa in New Mexico, twenty miles from the nearest outpost, with neither running water nor power, and built herself an adobe house, where she lived for the next ten years. She was 57. In 1971 she began painting again and continued without interruption until she died in 2004, aged 92..." 
from Nicolas Spice's piece in the London Review of Books on the Agnes Martin show at Tate Modern:

Martin was born in Saskatchewan. I wonder to what extent was influenced by the starkness  of her native landscape, not to mention the dominant grid pattern of settlement there? Life lived in between the lines.