interface Shape
  method area() as word
end interface

interface Named
  method id() as byte
end interface

class Box implements Shape
  public method area() as word
    return 1
  end method
  public method reset()
  end method
end class

class Can
end class

program Main
  var w as word
  var ok as boolean
  var b as Box
  var k as Can
  var s as Shape
  var n as Named
  var arr as word[4]
  var arr2 as word[4]
  ok = null
  b = s
  n = s
  n = b
  k = b
  s = k
  arr = 5
  w = arr
  arr = arr2
  w = b.reset()
  b = null
  s = b
  n = null
  ok = b = k
  ok = s = n
  ok = n = b
end program