svg`<svg width="${w}" height="${h}" >
<rect width="${w}" height="${h}" stroke="blue" fill="none" />
<g transform="translate(${(w - nx * gridSize) / 2}, ${(h - ny * gridSize) / 2})">
${array(ny).map(j => {
const s = gridSize / 2
return array(nx).map(i => {
const x = i * gridSize + s
const y = j * gridSize + s
return `<g transform="translate(${x}, ${y}) rotate(${randInt(4) * 90})">
<line
stroke="black"
fill="none"
x1="${-s}" y1="${-s}"
x2="${s}" y2="${s}"
/>
</g>`
}).join('\n')
}).join('\n')}
</g>
</svg>`