how can my lines become thicker (bold)when mouse is over?

import processing.sound.*;

Amplitude amp;
AudioIn in;

float z = 0;
int value = 0;
void setup() {
  size(800, 800);
  background(255);

  // Create an Input stream which is routed into the Amplitude analyzer
  amp = new Amplitude(this);
  in = new AudioIn(this, 0);
  in.start();
  amp.input(in);
}

void draw()
{
  noStroke();
    fill(0, 10);

    stroke(0, 100, value);
  println(amp.analyze());

  if (amp.analyze() > 0.03){
  for (float y = 0; y < height; y = y + 20) {

        for (float x = 0; x < width; x = x + 1) {
            point(x, y + map(noise(x/150, y/150, z), 0, 1, -100, 100));
        }
    }
    // when y is 500 the program will move forward. In this case increment z
    z = z + 0.02;

  } else {
    background(255);

  }}