I was brushing my teeth when I noticed a crumb on the windowsill. Closer inspection revealed that it was a silver birch tree seed. To the naked eye, a silver birch seed might just look like a speck, but a magnifying glass reveals it as one of nature’s works of art. Protected in a case with two tiny wings and a couple of antennae-like protuberances, the seeds closely resemble tiny moths. Each one is also a masterpiece of engineering, able to fly for up to a mile on a good following wind.