Langdon's affection for the yin/yang symbol was conjoined by his interest in western scientific symbols: the normal bell curve, wave pattern, the infinity symbol, and spirals and helices, and in the mid 1980s he produced a body of work in various media exploring the relationships among those symbols. In response to the changes in the graphic design world brought about by the advent of the Macintosh, Langdon resumed his painting career enthusiastically in the mid-1990s. Since then he has produced many paintings that explore his combined interests in words, symmetries, and optical illusions.