DouKaku?

require 'Win32API'

GetKeyState = Win32API.new('user32', 'GetKeyState', 'I', 'I')

pause = false
can_toggle_pause = true

Thread.start {
  loop {
    unless pause
      print 'a'
      sleep 1
    else
      sleep 0.1
    end
  }
}

loop {
  key_state = {:p => (GetKeyState.call(?P)[7] == 1),
               :q => (GetKeyState.call(?Q)[7] == 1)
  }
  exit if key_state[:q]
  if key_state[:p]
    if can_toggle_pause
      pause = !pause
      can_toggle_pause = false
    end
  else
    can_toggle_pause = true
  end
  sleep 0.05
}