Possible implementation of Pong with an imaginary API I need to just build

pong.rb

Shoes.app width: 800, height: 600 do

  tick 60 do
    stop_ticking if @right_player.won? or @left_player.won?
    alert "Right Player Wins!" if @right_player.won?
    alert "Left Player Wins!" if @left_player.won?
  end

  moving_element :ball do
    location top: 400, left: 300
    velocity horizontal: 50, vertical: 50
    shape :circle, radius: 50
    on_tick do
      move next_position
    end
    on_collision do |collided_element|
      velocity horizontal: :reverse
    end
    on_exiting_canvas do |side|
      if side == :top or side == :bottom
        velocity vertical: :reverse
      else
        move starting_position
        score_point side
      end
    end
  end.draw

  element :paddle do
    shape :rectangle, height: 100, width: 25
  end

  player :pong_player do
    attr_accessor :paddle
    winning_score 10
    speed 10
    on_join do |options|
      score 0
      self.paddle = options[:paddle]
    end
    on_up { paddle.move_relative(top: speed*-1) }
    on_down { paddle.move_relative(top: speed) }
  end

  @left_paddle = element(:paddle) { location top: 400, left: 0 }.draw
  @left_player = player(:pong_player).join(paddle: @left_paddle, up_key: "k", down_key: "j")
  @right_paddle = element(:paddle) { location top: 400, left: 800 }.draw
  @right_player = player(:pong_player).join(paddle: @right_paddle, up_key: "d", down_key: "s")

  def score_point side
    @right_player.score += 1 if side == :left
    @left_player.score  += 1 if side == :right
  end
end