submission by jtoy
var cols
var rows;
var scl = 20;
var w = 2000;
var h = 1700;
var flying = 0;
var  terrain = []

function setup() {
  createCanvas(600, 600,WEBGL);
  cols = w / scl;
  rows = h / scl;
      for(x = 0; x < cols; x++) {

    terrain[x]=[]
        for(y = 0; y < rows; y++) {

      terrain[x][y] = 0
    }
  }

}

function draw() {
  flying -= 0.1;

 yoff = flying;
  for(y = 0; y < rows; y++) {
    xoff = 0;
    for(x = 0; x < cols; x++) {
      terrain[x][y] = map(noise(xoff, yoff), 0, 1, -100, 100);
      xoff += 0.2;
    }
    yoff += 0.2;
  }

  background(0);
  stroke(255);
  noFill();

  translate(width/2, height/2+50);
  rotateX(PI/3);

  translate(-w/2, -h/2);

  for(y = 0; y < rows - 1; y++) {
    beginShape(TRIANGLE_STRIP);
    for (x = 0; x < cols; x++) {
      vertex(x * scl, y * scl, terrain[x][y]);
      vertex(x * scl, (y + 1) * scl, terrain[x][y+1]);
    }
    endShape();
  }
}