ruby2.3-tcltk 2.3.0-5ubuntu1 (s390x binary) in ubuntu xenial

 Ruby is the interpreted scripting language for quick and easy
 object-oriented programming. It has many features to process text
 files and to do system management tasks (as in perl). It is simple,
 straight-forward, and extensible.
 .
 This package provides Ruby/Tk, Ruby bindings for the Tk graphical user
 interface toolkit.