this introduced me to the awesome 凹 and 凸 kanji characters in japanese/chinese, meaning concave and convex respectively; plus 𠱂 which apparently means 'to rebuke/retort' i.e. a 'sharp' response (lol?) - see https://en.wiktionary.org/wiki/%E5%87%B9 and https://en.wiktionary.org/wiki/%E5%87%B8