Billed as "The World’s Most Difficult Puzzle" and produced by Springbok Editions of New York City in 1964, this cardboard puzzle sparked resurgence of interest in jigsaw puzzles which had fallen on hard times after WW II. Springbok collaborated with major art museums to produce quality cardboard puzzles from prints of artwork in their collections, and included in puzzle boxes descriptions of the artists and works of art (as well as color copies). The puzzles helped familiarize the public with pictures at the museums and spurred attendance as assemblers wanted to see the actual works of art after laboring so long to assemble puzzles made from copies. Artist here is Jackson Pollock. Frequently, cardboard puzzles produced today are billed as "World’s Most Difficult Puzzle"; "Convergence" was the first of many.