"Two aspects of thinking in particular are pronounced in both creative and hypomanic thought: fluency, rapidity, and flexibility of thought on the one hand, and the ability to combine ideas or categories of thought in order to form new and original connections on the other. The importance of rapid, fluid, and divergent thought in the creative process has been described by most psychologists and writers who have studied human imagination. The increase in the speed of thinking may exert its influence in different ways. Speed per se, that is, the quantity of thoughts and associations produced in a given period of time, may be enhanced. The increased quantity and speed of thoughts may exert an effect on the qualitative aspects of thought as well; that is, the sheer volume of thought can produce unique ideas and associations. Indeed, Sir Walter Scott, when discussing Byron's mind, commented: "The wheels of a machine to play rapidly must not fit with the utmost exactness else the attrition diminishes the Impetus." The quickness and fire of Byron's mind were not lost on others who knew him. One friend wrote: "The mind of Lord Byron was like a volcano, full of fire and wealth, sometimes calm, often dazzling and playful, but ever threatening. It ran swift as the lightning from one subject to another, and occasionally burst forth in passionate throes of intellect, nearly allied to madness." Byron's mistress, Teresa Guiccoli, noted: "New and striking thoughts followed from him in rapid succession, and the flame of genius lighted up as if winged with wildfire."