Hidden Cities II and III reverse the direction of Hidden Cities I whose intricacies draw on so many outside references. Continuum is meant to be immediately accessible without insisting on any meaning outside itself. It indulges—to the point of saturation—my visceral fascination with light, time and, above all, space. What follows is not an explanation, but simply a list of some of the sources which may have piqued the curious. Making lists is one of life's pleasures which I hope to pass on while providing some insight into my strategies for diversion.

1. Hidden Cities From Italo Calvino's Invisible Cities: a fantastical account of the cities visited by Marco Polo as described to the emperor Kublai Khan. In the end the cities are revealed to be mysteriously all versions of Venice.

2. Continuum of space and time.

3. Galleria Victorio Emmanuele II The extravaganza bult in Milan, 1867. Stretched, spread and multiplied from two photographs taken from the same vantage point a century apart. One from the turn of the 19th century and one from the late 20th century.

4. Kaisergalerie The front façade on the looming structure: from a 1900 photograph of the Kaisergalerie, Berlin, 1873.

5. The precariously perched towers above the central glass structure: more elements, altered, from the Berlin Kaisergalerie.

6. Café Cerberus a reference to the three-headed dog guarding Hades (the three heads here being the real dog, his reflection and his shadow.) Hades was suggested to me by the the forked passages which lead to the far gates into two worlds (one of which has a dazzling light coming from it, while the other seems to open onto the jumble of a city.) The evocation of heaven and hell makes a full circle from the hopscotch game of Hidden Cities I. The hopscotch my wife played in 1930's Germany was known as Himmel und Hölle.

7. Biffi A contemporary shop of Milan fashion. Its first incarnation was as the Café Biffi, the first business to open in the Galleria in 1867. Its neighbor is the café where the aperitif Campari was invented by its founder Gaspari Campari, ca. 1880. Campari is a nectar of heaven or hell depending, it seems, on your taste.

8. Café Dome The line of chairs: from a Paris 1923 photograph by Eugene Atget of le café Dôme; the same chairs as in Hidden Cities I.

9. Three Men With canes, right. From a 1913 photograph by August Sander, three German farmers in their Sunday best. Here urbanized to suggest the need for a little afternoon aperitif.

10. The Crowd The early-evening strolling in groups that is traditional in Italian towns known as passeggiare la piazza. The throngs who have repaired to the tables are separated in time from the strollers by a century.

11. The Vaults The great vaulted roof under the glowing sky: an imaginary convex structure repeating in reverse the concave glass dome at the left. Escher meets Piranesi. Concave is convex is concave.

12. The Floor Mostly altered elements of the Milan Galleria. The floor stripes and medallions are an invention.

13. The Transparent Woman Lower left. A phantasm from the present, not yet fully clear, probably, like the others, just passing through.

14. The Sky From a photograph I took in the Yorkshire moors. The skies of islands are skies still low from their ocean origins. My own East Coast sky feels too high: I seem to be mysteriously more familiar with a fast moving Celtic sky as if returning to an ancient memory.

15. Medium First, a collage from photocopies of two centuries of the Galleria. Second, a full size transparency of the collage combined with a second Mylar sheet with my usual sugar/ink texture. Both sheets drawn on and scraped. Third, an etching on copper, capturing drawing with a gelatin resist gravure etching process. Fourth, engraving into the etched plate. Extensive, and my favorite part. Finally, a print on paper, with drawing and erasing touches on each impression. Time: surreal, alarmingly close to two years. Content: discoveries, stumbles, revision and elation. My continuum.