def setup
  @x = 50
  @y = 50
  fill(255, 0, 0)
end

def draw
  @x -= 5 if keyIsDown(LEFT_ARROW)
  @x += 5 if keyIsDown(RIGHT_ARROW)
  @y -= 5 if keyIsDown(UP_ARROW)
  @y += 5 if keyIsDown(DOWN_ARROW)
  background(220)
  ellipse(@x, @y, 30, 30)
end

def setup
  @diameter = 30
end

def draw
  # 107 and 187 are keyCodes for "+"
  if keyIsDown(107) || keyIsDown(187)
    @diameter += 1
  end

  # 109 and 189 are keyCodes for "-"
  if keyIsDown(109) || keyIsDown(189)
    @diameter -= 1
  end

  background(220)
  fill(255, 0, 0)
  ellipse(50, 50, @diameter, @diameter)
end