void setup() {
  size(893, 50);
}

void draw () {
  background(204);
noFill();
smooth();
float mouseVal = mouseX;
for (int x = 0; x < 893; x ++) {
  float n = norm(x, 0.0, 893.0);
  float val = pow(n, 4) * mouseVal;
  stroke(val);
  line(x, 0, x, 10);
  float negN = lerp(1.0, 0.0, n);
  float valSquare = pow(negN, 4) * mouseVal;
  stroke(valSquare);
  line(x, 5, x, 10);
  stroke(val);
  line(x, 10, x, 15);
  stroke(valSquare);
  line(x, 15, x, 20);
  stroke(val);
  line(x, 20, x, 25);
  stroke(valSquare);
  line(x, 25, x, 30);
  stroke(val);
  line(x, 30, x, 35);
  stroke(valSquare);
  line(x, 35, x, 40);
  stroke(val);
  line(x, 40, x, 45);
  stroke(valSquare);
  line(x, 45, x, 50);
}
}