The Swiss psychiatrist Hermann Rorschach would ask his patients to identify shapes hidden in ten ink-blots, believing that their answers revealed a range of psychological traits. The ink-blot test became a popular tool of psychiatry. When Warhol embarked on his series of Rorschach paintings, he incorrectly assumed that the test involved making inkblots as well as interpreting them. Had he been better informed, he later explained, he would simply have copied the original ten inkblots. Instead, he created his own, pouring paint across a large canvas and folding it over to create symmetrical, butterfly-like patterns. At the end of his career he had come full circle, using an ink-blot technique that recalls his early experiments with blotted-line drawings.