[font=Trebuchet MS][b][size=150]In addition, I made a generalization of epicycloid.[br]In the case of [color=#ff7700]epicycloid[/color], one smaller circle rolls on the rim of one bigger circle without slippage (it is [color=#ff7700]two-circle system[/color]).[br]Thus, I made the [color=#ff7700]three circle-system[/color] here above.[/size][/b][/font]