Design for an eight-sided fortress for an ideal city: half-plan and section

From the publication, Vincenzo Scamozzi. L'Idea della architettura universale' (Venice, 1615), part 1, book 2, ch. XXVI, between p. 193 & 194, plate 3. In the 1590s Scamozzi had been involved in the design of the ideal fortified town of Palmanova in north-east Italy and his experience of that design was reflected in book 2 of part 1 which was devoted to military architecture.