createCanvas(700, 700);

  const rows = 100

  const cols = 100

  const diameter = width/rows;

  let counter = 0;

  const total = rows * cols;

  for (let i = 0; i < rows; i++) {

    for (let j = 0; j < cols; j++) {

      const x = j * width/cols

      const y = i * height/rows

      const rnd = random()

      const colour = rnd > 0.05 ? color("red") : color("black")

      if (rnd <= 0.05) counter++

      fill(colour)

      noStroke()

      rect(x , y, diameter, diameter)

    }

  }

  console.log(counter / total)

}

​