TED】サキ・マフンディクワ。古代アフリカのアルファベットに見る創意とエレガンス (Saki Mafundikwa: Ingenuity and elegance in ancient African alphabets) (【TED】Saki Mafundikwa: Ingenuity and elegance in ancient African alphabets (Saki Mafundikwa: Ingenuity and elegance in ancient African alphabet