“Combinatory play seems to be the essential feature in productive thought.”

Wallerstein (1979) The Capitalist World-Economy. p. 15.

Source: Economics Of The Welfare State (Fourth Edition), Chapter 4, State Intervention, p. 73

The Nature of Time (1961) as quoted by Douglas Martin, "Gerald J. Whitrow, 87, Author Of Philosophic Tomes on Time" The New York Times (June 27, 2000)

Source: The Courage to Be (1952), pp. 108-109
Context: What is the end of all the magnificent means provided by the productive activity of American society? Have not the means swallowed the ends, and does not the unrestricted production of means indicate the absence of ends? Even many born Americans are today inclined to answer the last question affirmatively. But there is more involved in the production of means. It is not the tools and gadgets that are the telos, the inner aim of production; it is the production itself. The means are more than means; they are felt as creations, as symbols of the infinite possibilities implied in man’s productivity. Being-itself is essentially productive.

Source: Dry

Answer to a survey written by the French mathematician Jaques Hadamard, from Hadamard's An Essay on the Psychology of Invention in the Mathematical Field (1945). Reprinted in Ideas and Opinions (1954). His full set of answers to the questions can be read on p. 3 here http://www.pitt.edu/~jdnorton/Goodies/Einstein_think/index.html.
1940s
Context: The words or the language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The psychical entities which seem to serve as elements in thoughts are certain signs and more or less clear images which can be "voluntarily" reproduced and combined. There is, of course, a certain connection between those elements and relevant logical concepts. It is also clear that the desire to arrive finally at logically connected concepts is the emotional basis of this rather vague play with the above-mentioned elements.... The above-mentioned elements are, in my case, of visual and some muscular type. Conventional words or other signs have to be sought for laboriously only in a secondary stage, when the mentioned associative play is sufficiently established and can be reproduced at will.

Quotes from him, Csillag születik (talent show between 2011-2012)

Blood Meridian (1985)

Source: After Dark