Four historic cities rendered as street tribute posters in 2x2 grid

2x2 grid, 16:9, do this for 4 historic cities: class StreetTributePoster:
    def __init__(self, TOPIC):
        s = infer(TOPIC)                       # word, figure+action, glyphs, accent, tagline
        self.s = s

    def build_weave(self):
        back, front = split_strokes(self.s.word)          # some strokes behind figure, some in front
        return [ Layer(z=1, strokes=back),
                 Layer(z=2, figure=self.s.figure),        # the weave: figure BETWEEN stroke sets
                 Layer(z=3, strokes=front) ]

    def render(self):
        return compose( ground=dark+patina,
                        word=brush_hero(self.s.word, drips=True, dry_brush=True),   # S₁
                        weave=self. build_weave(),                                    # S₂
                        palette={BLACK, WHITE, self.s.accent, muted_secondary},      # S₃ (≤4)
                        orbit=[vertical_script, emblem_object, flora, handwritten_tagline],  # S₄
                        layout=DENSE_BALANCED )                                      # S₅

    def verify(self, img):
        assert brush_texture(img.word) and drips(img.word) and thumb_legible(img.word), "S₁"
        assert figure_between_strokes(img) and not photoreal(img.figure),               "S₂"
        assert color_count(img) <= 4 and grunge(img),                                   "S₃"
        assert glyphs_from_topic(img, self.s) and handwritten(img.tagline),             "S₄"
        assert hierarchy(img)==[WORD, FIGURE, GLYPHS] and balanced(img),                "S₅"

StreetTributePoster(TOPIC).render()