Using the Keyboard

int x = 200, y = 200;
color c = color(255);

void setup()
{
  size(600,600);
}

void draw()
{
  fill(c);
  ellipse(x, y, 200, 200);
}

void keyPressed()
{
  if (key == CODED)
  {
    if (keyCode == UP)
      y -= 10;
    else if (keyCode ==DOWN)
      y += 10;
    else if (keyCode == LEFT)
      x -= 10;
    else if (keyCode == RIGHT)
      x += 10;
  }
  else if (key == 'r' || key == 'R')
    c = color(255,0,0);
  else if (key == 'y' || key == 'Y')
    c = color(255, 255, 0);
  else if (key == 'w' || key == 'W')
    y -= 10;
  else if (key == 'a' || key == 'A')
    x -= 10;
  else if (key == 's' || key == 'S')
    y += 10;
  else if (key == 'd' || key == 'D')
    x += 10;
}