require 'ruby2d'
set title: '4'
set width:  600
set height: 40
set background: 'white'
x=0;
on :key_down do |e|
  t = Text.new(x:x, text: e.key, size: 30, font: '/usr/share/fonts/truetype/ubuntu-font-family/Ubuntu-R.ttf', color: "random")
  x = x+t.width
end
show