This is one segment of the outstanding 24-foot-long drawing by Joe Sacco of the first day of the battle of the Somme from his concertina book The Great War: July 1, 1916 (an illustrated panorama with an essay by Adam Hochschild. Jonathan Cape, 2013, 56pp, £20). At first, the mass of figures shuffling through trenches appear to be Where’s Wallys, then peering closer you see that they are all individual characters conversing, responding, relating to each other and life. Sacco’s genius is to create a graphic experience that draws your eye through through an arc of time and the parting and joining ribbons of narrative. It is a brilliant, visual, Greek tragedy. We are taken on a 24 hour journey — a trajectory from order to chaos — from general Haig’s morning walk around his chateau to the mass graves of 21,000 the following day. The fascination of this picture, like all the greatest panorama drawings, is in the detail — the saucepans and latrines and rum rations, the information and incidents taken from photographs and records and primary sources. At the very end of the day, at the end of the sheet of paper, the column of troops on the horizon beyond the graves, marches back towards the beginning. This tiny detail supplies the unseen narrative for all the awful days to follow.