Overlooking the harbour and city from Fred Ambler Lookout in Parnell, the large, ladder-like forms of this artwork represent the sails, masts and cranes that mark Auckland's Waitematā Harbour. The ambitious sculpture was created by late Mexican artist Helen Escobedo in 1971 for the International Sculpture Symposium. Organised by the NZ Society of Sculptors and Painters Inc. the symposium was part of Auckland’s centenary celebrations.

'Signals' consists of four 15-metre-high stainless steel towers, each with four sets of rungs that are coloured with vivid diagonal flashes of blue, yellow and red. While this is a large-scale work, it still has an element of lightness as it moves in the wind above the port and railway.