Line-printer art of the mainframe era: a fixed grid of characters on fan-fold green-bar paper, tone built from how much ink a glyph lays down, overstrike to darken. H. Philip Peterson's 1965 Mona Lisa, printed in numerals standing for grey levels, is the canonical sheet.
The output device had no addressable pixels, only characters, so the greyscale was glyph density. Printer cells were taller than wide, which stretches everything, and the ribbon faded across a long print. The paper's green bars were there to help clerks read columns of figures.
The figure is rasterised onto a grid of 53 by 25 cells and each cell picks a glyph from a ten-step density ramp. Rim cells and the glasses are double-struck. Every line gets its own ribbon alpha and a little hammer jitter, and the green bars run behind.