Incendies ★★★★

Not sure the maths add up to that last plot knot (although an early mention of the Collatz conjecture is a sneaky clue), but otherwise this is a solid, sensitive Greek tragedy about the unimaginably awful shit that passes for modern warfare in the Middle East. Interesting in the context of Arrival too; Villeneuve has a real bee in his bonnet for delivering answers to mysteries you didn't realise were staring you in the face all along.