Background — A search for the title in this journal.
Grothendieck was at times excited about space:
"The notion of space is certainly one of the oldest
in mathematics. It is fundamental to our 'geometric'
perspective on the world, and has been so tacitly
for over two millenia. It's only over the course of the
19th century that this concept has, bit-by-bit, freed
itself from the tyranny of our immediate perceptions
(that is, one and the same as the 'space' that
surrounds us), and of its traditional theoretical
treatment (Euclidean), to attain to its present
dynamism and autonomy. In our own times it has
joined the ranks of those notions that are most freely
and universally employed in mathematics, and is
familiar, I would say, to every mathematician
without exception. It has become a concept of multiple
and varied aspects, of hundreds of thousands of faces…."
— fermentmagazine.org/rands/promenade12.html
An aspect not so familiar: Diamond Space.