3d grid perlin noise for loop not working

// Starter sketch for this challenge: 

// https://www.notion.so/neillzero/offset-a-3d-terrain-grid-with-perlin-noise-440a0bee9ff54bce82dad104a5e0bdc5

let vOffset = 5000

let hOffset = 500000

let dOffset = 600000

​

​

function setup() {

  createCanvas(windowWidth, windowHeight, WEBGL);

  // debugMode()

  const cam = createCamera();

  cam.setPosition(300, -200, 600)

  cam.lookAt(0, 0, 0)

}

​

​

​

function decideColour(n) {

  if (n > 0.75) {

    return "white"

  } else if (n > 0.65) {

    return "gray"

  } else if (n > 0.5) {

    return "green"

  } else if (n > 0.4) {

    return "yellow"

  } else if (n > 0.3) {

    return "skyblue"

  } else {

    return "navy"

  }

}

​

function draw() {

  let noiseScale = 0.003

​

  background('white')

  orbitControl(5, 5, 0.2);

​

  const gridHalfWidth = 40;

  const cellSize = 10;

​

  for (let gridX = -gridHalfWidth; gridX < gridHalfWidth; gridX++) {

    for (let gridZ = -gridHalfWidth; gridZ < gridHalfWidth; gridZ++) {

      const x = gridX * cellSize;

      const z = gridZ * cellSize;

      let n = noise(hOffset + x * noiseScale, dOffset + z * noiseScale); // Offsets are added to combatt symmetry 

      let y = 0

      if (n < 0.4) {

        let y = n * -100

      }// why can't I use a for loop?

      //const y = Math.max(n, 0.4) * -100; //height of each cell.  change this to be based on perlin noise at x,z

​

      push();

      translate(x, y, z)

      fill(decideColour(n))

      box(cellSize, cellSize, cellSize);

      pop()

    }

  }

​

}