rects = gridLengths.map(
(rowLengths, i) => rowLengths.map(
(width, j, arr) => htl.svg.fragment`<rect
y=${TILE_HEIGHT * i}
x=${d3.sum(arr.slice(0, j)) * TILE_WIDTH}
height=${TILE_HEIGHT}
width=${width * TILE_WIDTH}
fill=${getColor(j + (width / 2))}
/>`
)
).flat()