A poster by designer/collector Gielijn Escher (1945–) for an exhibition about “young Dutch art” at De Lakenhal in Leiden in 1968, screen printed by Levisson.
The typography is set in all-lowercase Helvetica. Note the lowered hyphens, used as dashes. This might be a reference to early computing. The use of underscores (as word separators) dates back to the late 1960s with the with the rise of computers and programming languages. This style of writing was later called Snake case, in which each space is replaced by an underscore _ and the first letter of each word was set in lowercase.