Short curved strokes comb most of the square, finer and denser across the upper left, coarser and airier below, changing along one straight diagonal. Flat-sided regions bite into that combing and the strokes stop at their edges: two are left as bare paper, one at the left and one running out of the top right corner, and the third is packed with taut straight chords and holds all the black in the drawing.
One drawing rather than a generative program, and vector rather than pixels: strokes in a single ink, sized in millimetres, so the file above can go to a pen plotter or a laser as it is.