William Pye, Pangolin, Kings Place, London, Osborne Samuel, London

William Pye's large water sculptures are almost a commonplace in regenerative city centres, public gardens and business centres. They are bewildering in their apparent defiance of nature in controlling water flow to create new dimensions for metal and stone forms.

These two exhibitions work as a double-barrelled retrospective to show, in small, where Pye's public cynosures came from. At Osborne Samuel, only one of the 20 pieces has flowing water – a maquette for a part of the piece in the Prince of Wales's Highgrove garden – while the canal-side at Kings Place is ideal for ten human-size water pieces.

These works are endlessly inventive. Coraslot is a waist-high bronze cup brim-full with water, which appears to have a rectangular hole in the middle without disturbing the meniscus; Archimedes is an adaptation of the ancient solution to conveying water upwards, in which water spouts out of a turning stainless-steel spiral to pour precisely into an apostrophe-shaped hole moulded into a bronze cylinder. The question of how it is done quickly melts in the fascination of the flow.

At Osborne Samuel, the emphasis switches from the liquid to the geometric of Pye's smaller pieces, in which sometimes rhomboidal shapes are given new relationships when connected by stainless-steel strings. Here it is clear that Pye's primal inspiration is landscape, and that his work is not a defiance of nature but a collusion. Small bronze essays in convex and concave forms working together are seen next to a photograph of the four-metre high Cader Idris in Cardiff Central station.

The exhibitions coincide with the publication of Pye's repletely illustrated autobiography, William Pye: His Work and His Words, in which the mysteries of his solutions as well as his inspirations are explained.

Pangolin: to 24 December (020 7520 1490); Osborne Samuel Gallery: to 2 October (020 7493 7939)