Shoes 4 Ski Jumping Game. Inspired by [Sebastjan's post](http://librelist.com/browser//shoes/2013/1/13/thank-you/) in Shoes ML. But, this is not a game, just a tiny example to learn Shoes 4. ;-)

ski_jumping.rb

class Skier
  def initialize app
    app.strokewidth 2
    @x0, @y0 = 0, 20
    @img1 = app.oval @x0 + 25, @y0 - 20, 5, 5
    @img2 = app.line @x0 + 5, @y0, @x0 + 25, @y0 - 15
    @img3 = app.line @x0 + 5, @y0 - 13, @x0 + 20, @y0 - 15
    @img4 = app.line @x0, @y0, @x0 + 30, @y0
    @img5 = app.line @x0, @y0, @x0 + 30, @y0 - 10
    @img5.hide
  end
  def move x, y
    @img1.move @x0 + x + 25, @y0 + y - 20
    @img2.move @x0 + x + 5, @y0 + y - 15
    @img3.move @x0 + x + 5, @y0 + y - 13
    @img4.move @x0 + x, @y0 + y
    @img5.move @x0 + x, @y0 + y - 10
  end
  def change_ski_angle
    [@img4, @img5].each &:toggle
  end
end

Shoes.app width: 600, height: 400 do
  back = image File.join(File.dirname(__FILE__), 'back_image.png')
  s = Skier.new self
  a = animate 5 do |t|
    v = 0.2*t**2
    x = v * Math.cos(Math::PI*0.2) 
    y = v * Math.sin(Math::PI*0.2) 
    t < 40 ? s.move(x, y) : (back.move(40 - t*4, -t); @air = true)
    a.stop if t > 80
  end
  keypress do |k|
    s.change_ski_angle if @air and k == " "
  end
end

Inspired by Sebastjan's post in Shoes ML. Download back_image.png and run with Shoes 4.
Watch a demo.

Watch an updated demo.