Signer’s works have acquired the label ‘time-sculpture’. They share traditional sculpture’s concern with the crafting of physical materials in three dimensions, but they extend that concern into what may or may not be characterised as the fourth dimension: the dimension of time. Time-sculpture investigates the transformation of materials through time, focusing the viewer’s attention on the experience of the event, the changes wrought, and the forces involved. Variously combining three-dimensional objects, live action, still photography and moving-image documentation, Signer’s time-sculptures frame episodes of the containment and release of energy − always with ingenuity, often with captivating, epigrammatic swiftness and irresistible humour. In Cap with Rocket (Mütze mit Rakete 1983), for example, a length of string connects a firework and a knitted hat that Signer has pulled over his head. The firework is ignited; it shoots into the air and whisks the hat away, revealing the artist’s face. In Stool − Kurhaus Weissbad (Hocker − Kurhaus Weissbad 1992) a small explosion triggers the catapulting of a four-legged stool out of a window; the stool sails through the air and crashes to earth. In Kamor (Kamor 1986) a gunpowder explosion at the summit of a small mountain in the Swiss canton of Appenzell produces a burst of flame and a plume of smoke and momentarily lends the summit the appearance of a live volcano. In Attaché Case (Aktenkoffer 1989/2001) a concrete-filled briefcase is taken on a short ride in a fast machine − a helicopter, to be precise. At a height of about a hundred metres it is dropped. Like a meteorite, it plummets into a grassy field and gouges a deep crater in the turf.