Celebrating the four ages of man, eight huge, semi-abstract paintings create a carnival atmosphere in the Serpentine’s central gallery. The freshness of Childhood is characterised by flowers, petals and stamens floating on a blue ground. The passions of Youth warrant a ground of hot orange crammed with circles and spirals jostling for space like amoeba in a petrie dish. Adulthood is dominated by a large, yellow gourd-like shape on a lavender ground; dancing in attendance are looping letters and clover-leaf swirls.

From its title, you could be misled into dismissing this show as narrow and self-referential: a small exhibition in a small gallery curated by a Belgian artist concerned only with his own countrymen. In fact, it is something of a survey, featuring works with influences that range from Piet Mondrian, Ad Reinhardt and Lucio Fontana, to the Color Field painters.

One of the earliest surviving sculptures by Barbara Hepworth is a toad made from a khaki-coloured, translucent stone; you can imagine it cool and heavy in your hand, not so very different from the animal itself, in fact. Made nearly 30 years later, the monumental sculptures carved from African guarea wood are almost unbearably touchable, each one with its dark, glossy exterior cracked open to reveal an inside as creamy as a conker. But while we are denied the pleasure of touching these objects, looking at Hepworth’s work is in itself a gloriously tactile experience.

Light. Light banishes the shadows where monsters lurk and where ghosts rattle their chains. “Give me some light, away!” cries the usurping king in Hamlet as his murderous deed is exposed by the trickery of art. What guilt plagues and seizes his conscience, and yet Claudius, conflicted, cannot pray. He must, therefore, remain a captive among the ghosts and the monsters where no light may fall.

In 1967 when she produced Syncopated Rhythm (main picture), Sonia Delaunay was 82; far from any decline in energy or ambition, the abstract painting shows her in a relaxed and playful mood. Known as The Black Snake for the sinuous black and white curves dominating the left hand side, this huge, two and a half metre wide canvas is deliciously varied.

The Iranian-born New York resident painter YZ Kami, now in his mid-fifties, continually plays with our hunger to look at “reality” while being seduced by abstraction and repetition. In 17 canvases, painted over the past two years, Kami explores two distinct and recognisable styles or idioms that however much in common they have with contemporary concerns he has made his own. The results are both powerful and pleasurable. 

Sotto Voce is a collection of white paintings, sculptures and reliefs made by European, British and North and South American artists from the 1930s to 1970s. An accompanying book explains why this non-colour has appealed to so many artists in so many countries over such a long period of time.

Some documentaries can feel like trying to view a desert landscape through a telescope. The need for tight focus on too large a subject can leave you constantly aware that there’s important stuff going on out of eyeshot. The stuff you can’t see becomes a constant irritant, like a pending tax return, or David Starkey. Kraftwerk: Pop Art, in significantly narrowing its focus, was more like studying a Petri dish under a microscope – and just as fascinating.

From an apparently simple idea stems a very confusing exhibition. Here’s the idea: taking the seminal black square painted by Russian artist Kazimir Malevich as its starting point – in fact, a rectangle, with the small and undated Black Quadrilateral the first of three Malevich paintings – we are invited, over the span of a century and across a number of continents, to explore the evolution of geometric abstraction and its relation to “ideas of utopia”.  

Late Titian, Late Rembrandt, Late Picasso, Late Matisse…. What is it with Late that seems to give some artists a Golden Age irradiated by a kind of sublime carelessness, a genuine sense of anything goes? A life spent learning means that in the end it might be worn lightly and the imagination set free. Of course, such a sublime coda is not given to all, as many an artist descends into self-parody, rather than ascending into a kind of upward free-fall.