What is the glyph origin of '奇'?
The discussion on zdict basically explains that the Oracle bone script morphed (讹变) into its current form, but this transformation did not follow standard rules.
The original Oracle bone script shows a man riding a horse, which means &quot;to ride&quot; (i.e. what 骑 means today), but when small seal script was developed, the horse morphed into 可, which violates the usual practice of keeping the meanings the same. The character also acquired the meanings of &quot;unusual&quot; or &quot;strange&quot;:


甲骨文“奇”字，人骑在马上，小篆“奇”字“马”讹变为“可”（“字源字形”栏目），本义跨坐、骑坐，“骑”本字，借为①特殊的、不常见的：奇怪、奇异、稀奇，②出人意料的、令人不测的：奇兵、奇计、出奇制胜，又借为：
◎ jī 单数、与“偶数”相对：奇数、奇偶、奇函数。