The relationships between theory and practice are far more partial and fragmentary. On one side, a theory is always local and related to a limited field, and it is applied in another sphere, more or less distant from it. The relationship which holds in the application of a theory is never one of resemblance. Moreover, from the moment a theory moves into its proper domain, it begins to encounter obstacles, walls, and blockages which require its relay by another type of discourse (it is through this other discourse that it eventually passes to a different domain). Practice is a set of relays from one theoretical point to another, and theory is a relay from one practice to another. 

No theory can develop without eventually encountering a wall, and practice is necessary for piercing this wall.

Gilles Deleuze, Intellectuals and power: A conversation between Michel Foucault and Gilles Deleuze

Sol LeWitt
All Combinations of Arcs from Corners and Sides; Straight, Not-Straight and Broken Line
1975

Lisa Hoke
Eureka
1989

Shigeko Kubota
Niagara I
1985

And isn’t this the strength of Lacan, to have saved psychoanalysis from the frenzied oedipalization to which it was linking its fate - to have brought this salvation even at the price of a regression, and even though it meant the unconscious would be kept under the weight of the despotic apparatus, that it would be reinterpreted starting from this apparatus, the Law, and the signifier - phallus and castration, yes! Oedipus, no! - the despotic age of the unconscious.

Anti-Oedipus: Capitalism and Schizophrenia, Gilles Deleuze and Félix Guattari

Second, we make no distinction between man and nature: the human essence of nature and the natural essence of man become one within nature in the form of production or industry, just as they do within the life of man as a species. Industry is then no longer considered from the extrinsic point of view of utility, but rather from the point of view of its fundamental identity with nature as production of man and by man. Not man as the king of creation, but rather as the being who is in intimate contact with the profound life of all forms or all types of beings, who is responsible for even the stars and animal life, and who ceaselessly plugs an organ-machine into an energy-machine, a tree into his body, a breast into his mouth, the sun into his asshole: the eternal custodian of the machines of the universe.

Anti-Oedipus: Capitalism and Schizophrenia, Gilles Deleuze and Félix Guattari