Present in Mario Merz from the beginning, the image of the cosmic spiral becomes the distinctive feature of his work, displaying the sequence of numbers discovered by the mathematician Leonardo Fibonacci and chosen by the artist to represent the natural processes that regulate growth. The spiral represents the relation between art, mathematics and cosmology.
The spiral was also the protagonist of one of his famous shows of 1990: "The space is curved or straight?". It was a total work created with iron, bundles of wood, glass, neon and newspapers and with it Mario Merz applied his conviction to incorporate all areas of a museum in his work, rather than simply to show his works in architectural space. The installation was flowing from outside to inside, from the museum at the square, creating a path along three hundred yards of charm that gave the impression which the nature invaded the museum.