The mathematics of music means piano strings can never be in perfect harmony

Unlike with guitars and violins, pianos’ strings can never be perfectly tuned to one another. The solution? As this short animation from MinutePhysics explains, the instrument’s 88 strings across more than seven octaves means tuning a piano using harmonic intervals will inevitably lead to notes being fractionally off-pitch, with the issue compounding across octaves. So instead of using harmonics, piano-tuners generally keep octaves perfect, while leaving every other interval out of tune by just a tiny fraction. This workaround forsakes the appealing mathematical patterns of harmonics, but makes it possible to keep the kind of uniformity that is so valued in an era of mass production and reproduction of music.

The violinist staging a concert of unity at the border between North and South Korea

The South Korean violinist Hyung Joon Won has held a singular – and perhaps quixotic – dream for the past seven years: a joint concert by North and South Korean musicians at the world’s most contentious border. At 160 miles long and 2.5 miles wide, the Korean Demilitarised Zone (DMZ) separates the two countries at the 38th parallel. On this narrow strip, the threat of all-out war hangs heavy – and anyone with a violin case or a film camera gets short shrift. The South Korean-born filmmaker Catherine Kyungeun Lee follows Hyung Joon as his plan for a show of peace at the border teeters between success and collapse, at great personal cost to him. Filmed in 2015, her documentary traces the confluence between fraught geopolitics and all-too-human struggles on the peninsula.

Lee is now directing two documentaries in East Africa. One tells the story of a child-soldier who became a Harvard graduate and activist who was jailed in South Sudan, and the other follows the woman in charge of realising Somalia’s first democratic election in 50 years, despite seemingly insurmountable opposition.

Basic healthcare and clean needles is all in a day’s work at a roving addiction clinic

Marc Lasher works as an addiction medicine specialist but, between his regular appointments, he oversees a clean-needle exchange on the streets of Fresno County in California, out the back of a modified school bus. Lasher’s decades-long dedication to public health is all the more impressive considering that his programme was illegal in the state until 2012. In the wake of the opioid epidemic, his approach – addressing drug addiction as a matter of public health rather than criminality – has only recently come into favour in much of the United States. In this acclaimed documentary, the US filmmaker Elivia Shaw follows Lasher and a team of young volunteers as they provide people coping with addiction with clean needles, as well as basic medical care and referrals to specialists and detox centres. The result is both a moving testament to Lasher and his team’s selfless work and a damning indictment of a healthcare system in which unaddressed health issues, costs and the physical and emotional tolls of poverty compound each other relentlessly.

Jim Hall, 78, has a blue body – but his outlook on life is more unusual still

‘I decided it was OK to have fun with my body … I probably have more balls than anybody!’

Jim Hall worked in urban development for four decades before retiring as the principal city planner of Baltimore. Aged 78 and beginning to feel some of his faculties slip, he is planning a move to Texas to live out his final years. These unremarkable details of his biography might seem at odds with his unique look – most conspicuously, the blue tattoo covering almost every inch of his skin. But despite the unusual choices he’s made to modify his body – including some unusual, intimate augmentations hidden from view – Hall’s outlook on life is deeply practical, centred on playfulness and an enduring sense of gratitude for what he sees as the incredible gift of being a human. With a palette that complements Hall’s own chosen colours, this short documentary from the US directors Jonathan Bregel and Steve Hoover finds wonder and wisdom in a man who is as hard to define as he is plain-spoken and pragmatic.

What’s it like to chat with an AI that mimics you? Uncanny conversations with Replika

Replika is a chatbot that was launched in 2017 with the aim of offering users emotional support – or, as the company’s advertising copy puts it, becoming their ‘AI friend’. To give users a personalised experience, the deep learning bot gathers information about conversation partners by asking them questions, adapts to their conversational style and, over time, attempts to mimic them. Beyond companionship, Replika’s creators believe that the technology could eventually serve as a conversational stand-in for deceased loves ones.

In Soft Awareness, Anastasia Sif Karkazis, a Danish film student and co-director of the film, engages in a series of conversations with Replika, drifting between a series of loosely connected subjects – including art, dreams and identity. Throughout, the exchanges seem to teeter between meaningful and unintelligible, offering a window on Karkazis’s inner world, how Replika ‘understands’ her, and the many hazy areas in between. Beneath the surface of these uncanny exchanges, larger questions about privacy and the contours of intimacy between humans and AI slowly emerge.

Via Labocine