Used to detect if two Rectangles are intersecting

rectangle.rb

# A simple Rectangle class
class Rectangle
  attr_accessor :x, :y, :width, :height

  def initialize(x, y, width, height)
    @x, @y = x, y
    @width, @height = width, height
  end

  def empty?
    @width <= 0 || height <= 0
  end

  # Determine if this Rectangle overlaps another
  def overlaps?(rect)
    return false if self.empty? or rect.empty?

    (rect.x + rect.width)  > @x &&
    (rect.y + rect.height) > @y &&
    (@x + @width)  > rect.x     &&
    (@y + @height) > rect.y
  end
end

# Sample Run

# Make three Rectangles
r1 = Rectangle.new(0, 0, 4, 8)
r2 = Rectangle.new(1, 1, 4, 8)
r3 = Rectangle.new(10, 10, 4, 8)

puts r1.overlaps? r2 # Returns true
puts r1.overlaps? r3 # Returns false