Autumn Swamp Wave

const CELL_SIZE = 30, CELL_CORNER_SIZE = 10;

const CELL_COLORS = ["#FE0000", "#FF7F00", "#FFCC00"];

​

let iniX, iniY;

let x, y, xc, yc, f, fc;

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(255);

​

  noStroke();

​

  iniX = random(-CELL_CORNER_SIZE, 0), iniY = random(-CELL_CORNER_SIZE, 0);

}

​

function draw() {

  x = iniX+CELL_SIZE, y = iniY, xc = 0, yc = 0;

  f = false, fc = 0;

  rectMode(RADIUS);

  while(y < height+CELL_CORNER_SIZE) {

    while(x < width+CELL_CORNER_SIZE) {

      fill(color((xc-fc)%3==0^f?"black":"white"));

      square(x, y, CELL_CORNER_SIZE);

      x += CELL_SIZE*2;

      xc++;

    }

    x = iniX + (yc%2?CELL_SIZE:0);

    xc = 0;

    y += CELL_SIZE;

    yc++;

    fc += f?0:1;

    f = !f;

  }

  x = iniX, y = iniY, xc = 0, yc = 0;

  rectMode(CORNER);

  while(y < height) {

    while(x < width) {

      const xyc = xc + yc;

      const order = xyc%4==3?1:xyc%4;

      fill(color(CELL_COLORS[order]));

      square(x, y, CELL_SIZE,

        xyc%2==1?CELL_CORNER_SIZE:0,

        xyc%2==0?CELL_CORNER_SIZE:0,

        xyc%2==1?CELL_CORNER_SIZE:0,

        xyc%2==0?CELL_CORNER_SIZE:0

      );

      x += CELL_SIZE;

      xc++;

    }

    x = iniX;

    xc = 0;

    y += CELL_SIZE;

    yc++;

  }

}