the slider in the top left directly influences the speed of the circle drawing and creation of the cardioid, as well as the quality of the cardioid. One is the slowest and six is the fastest. Input "2" when it asks you for the basic cardioid. -1 in the colour options is white, and everything else ranges from red (0) to red (200) Push the spacebar to erase. (Everything)
My personal favourite settings are 1,1,-1,120,0. Bring your cursor to the top left to change the settings, and click/tap or push any key to start.