Dan Flavin
«The Diagonal»

«From a recent diagram, I declared the diagonal of personal ecstasy (the diagonal of May 25, 1963), a common eight-foot strip with fluorescent light of any commercially available color. At first, I chose ‹gold.›... (I put the paired lamp and pan in position at an angle forty-five degrees above the horizontal because that seemed to be a suitable situation of resolved equilibrium but any other positioning could have been just as engaging.)»
[...]. The diagonal in its overt formal simplicity was only the installation of a dimensional or distended luminous line of a standard industrial device. Little artistic craft could be possible. [...] The diagonal, in the possible extent of its dissemination as common light repeated effulgently across anybody’s wall, had potential for becoming a modern technological fetish.»

(source: Dan Flavin, «‹...in daylight or cool white:› an autobiographical sketch,» Artforum 4, no. 4, December 1965, p. 24)