  Recently, the design study `Einstein gravitational wave Telescope' (ET) has
been funded within the European FP7 framework. The ambitious goal of this
project is to provide a conceptual design of a detector with a hundred times
better sensitivity than currently operating instruments. It is expected that
this will require the development and implementation of new technologies, which
go beyond the concepts employed for the first and second detector generations.
However, it is a very interesting and educational exercise to imagine a
Michelson interferometer in which conventional technologies have been pushed to
- or maybe beyond - their limits to reach the envisaged sensitivity for the
Einstein Telescope. In this document we present a first sketchy analysis of
what modifications and improvements are necessary to go, step-by-step, from
second generation gravitational wave detectors to the Einstein Telescope.
