After changing sliders, click green flag. Use Turbo. Changing sliders while drawing may mess up the drawing. Click green flag to clear the screen. This method, even in Turbowarp's turbo, it is not real-time, as it requires to synchronize 3 sprites
Thanks to @Heldlaw (and, of course, Philippe de La Hire, 1640-1718) for his fantastically simple strategy
