The immobile had been changed to mobility. - Albert Gleizes

If we wished to relate the space of the [Cubist] painters to geometry, we should have to refer it to the non-Euclidean mathematicians; we should have to study, at some length, certain of Riemann's theorems.

There is not a canvas of that time that does not foreshadow the overthrow of the foundations on which the human race thought itself firmly established, where it felt itself secure. At the moment when the Ballets Russes were at their height, when the Neo-Impressionists and Fauves had dispensed with the drawing style of the Renaissance because it could not contain the purity of the colour - these humbly painted, angular, grey, ascetic pictures were, really, an unwelcome sight. It was not any upheaval of a geological nature that they prefigured, but a cataclysm in the human order. No tremor of the earth was registered, but a tremor of the spirit that disturbed the intellect of civilised man, too long the slave of his immobilised senses. At last he was beginning to suspect that something dangerous was approaching.

We do not mechanically connect the sensation of white with the idea of light, any more than we connect the sensation of black with the idea of darkness. We admit that a black jewel, even if of a dead black, may be more luminous than the white or pink satin of its case. Loving light, we refuse to measure it, and we avoid the geometrical ideas of the focus and the ray, which imply the repetition-contrary to the principle of variety which guides us-of bright planes and sombre intervals in a given direction. Loving colour, we refuse to limit it, and subdued or dazzling, fresh or muddy, we accept all the possibilities contained between the two extreme points of the spectrum, between the cold and the warm tone.