When asked why he always seemed to paint the same landscapes around the Stour Valley, Constable said it was like hitting a nail with a hammer, that he might “finally drive it home.” There is something of that same thinking about Wladyslaw Mirecki's watercolours which, with odd exceptions, have continued to tackle the rolling contours of the East Colne Valley and the Chappel railway viaduct close to his Essex home for the last 30 years. It gives his work a quiet intensity and integrity that has won this Chelmsford-born (of Polish parents) self-taught painter, a huge following and many national prizes. Mirecki has been developing some other themes in recent years, coastal subjects and, most notably, old industrial sites returning to nature, but the sense of the silent watcher remains. Showing at Piers Feetham . THUMB nails by nicholas usherwood from the top: Wladyslaw Mirecki ‘Concrete and Contrails’ Ben Jones ‘Brecon Beacons’ Mhairi McGregor ‘Carradale Church’ With his grandfather a well known stonemason, there would seem to be an inevitability about Ben Jones, born and brought up in Builth Wells in mid Wales, becoming a stone carver. Not quite so, because we are talking about a 1960s London art education at that hotbed of welded iron, steel and resin sculpture – St Martin's, under Anthony Caro – and it has, in fact, taken him some four decades to find his way back to slate carving. But what a return! Here is an artist who has really found his voice, working at peak intensity within the Welsh landscape, and producing a whole stream of powerful slate landscape sculptures quite unlike anything else, works which use the particular vertical stratification of slate to render visible the very forces which created these landscapes in the first place. Showing at MoMa Machynlleth . There's a long connection between Scottish artists and Southern Europe going back to Ferguson, Peploe and the Scottish Colourists of the late 19th century. Mhairi McGregor, who graduated from Glasgow School of Art in 1993, shows herself to be very much part of the tradition that continues with vigour into the present day, as her new show at Roger Billcliffe , entitled simply 'Scotland and Italy' makes plain. A visit to Italy on a student scholarship sowed a seed and while she sees Scotland as her first love artistically, the crystalline Italian light also formed a crucial structural element in her intensely personal way of working. She takes the first sketched impressions of a landscape into the broader more simplified slabs of two or three gleaming colours that then form the basic characteristic of her highly distinctive style. It's not many art societies that boast a foundation membership that has included artists of the calibre of Ben Nicholson, Barbara Hepworth, Peter Lanyon and Bernard Leach (and Herbert Read as President. But then the Penwith Society, founded in St Ives in 1949, was really not your average society but rather a very conscious (and successful) attempt by the colony's leading lights to heal the abstract/figurative divisions that had been causing so much strife. It was, as the title of their 70th Anniversary show at Penwith Gallery suggests, 'A Society Like No Other' and it is celebrating it in some style with two exhibitions; this one tells the story of the Society from 1961, when they moved to their present home in a converted 'pilchard palace' in Back Road, St Ives, and a more historically oriented show ('Creative Tensions' at Penlee House, Penzance) traces its troubled beginnings.