It is a hypothetical reconstruction of the renowned burning mirrors of Archimedes.Several ancient Greek writers, including Archimedes, had written books “on burning mirrors”, but none of them have survived. Some medieval writers describe the burning of the Roman fleet by Archimedes using such mirrors, though it is not mentioned by ancient writers. One of them, Ioannis Tzetzes (1110-1180 A.D.) describes the burning of ships, from a distance within an arrow’s range, with the help of large hexagonal mirrors invented by Archimedes. He also mentions that these large hexagonal mirrors consisted of smaller mirrors, adjusted to the main one by means of blades and joints. This remarkable description indicates an adjustable mirror with variable focus. Although the alleged burning of ships is considered a myth, it would be quite possible to set moving ships on fire using large mirrors with adjustable focus. The reconstructed mirrors, using the right placement of pulleys (or gears alternatively) and the easy rotation of a single rope, follow an adjustable parabolic path, constantly changing its focus, according to the operator’s will. Archimedes had all the necessary knowledge in Mathematics and Engineering, as well as the technological skills in order to construct them.