An enigmatic sign, the figure/form ‘X’ conjures multiple meanings as text, number and symbol. Traversing cultures, beliefs and knowledge systems, an X can prohibit and denounce, approve and correct, combine and connect. From a mark found in prehistoric caves to the symbol for a female chromosome universal to all women and men, the figure-X conveys human presence. It encapsulates mystery and allure – an unknown variable, an axis on a map, sign of hidden treasure and a signifier for special qualities, the ‘X-factor’.