outline = ({
type: "Polygon",
coordinates: [
[
d3.range(w - 1).map(p => [p, 0]),
d3.range(h - 1).map(q => [w, q]),
d3.range(w, 0, -1).map(p => [p, h]),
d3.range(h - 1, 0, -1).map(q => [0, q])
]
.flat()
.map(projection.scale(w * (225 / 900)).translate([w / 2, h / 2]).invert)
]
})