ball.cr

class Ball 
  property :hits

  def initialize
    @hits = 0
  end 
end

def player(name : String, table : Channel)
  loop do
    ball = table.receive
    ball.hits += 1
    puts "#{name}: #{ball.hits}"
    sleep 1
    table.send ball
  end
end

table = Channel(Ball).new

spawn do 
  player("foo", table)
end

spawn do
  player("bar", table)
end

table.send Ball.new # game on; toss the ball
sleep 5 # increasing it, the game goes longer
table.receive
table.close