Introduction - If you have any usage issues, please Google them yourself
1. (Oval) painting a large area with customers and with customers to change the size of area fill oval. (The best can be determined for each random oval borders and fill colors, in which random color component values may also be called [to return a random number int type C language] function rand, again more than the 256 [available between 0 ~ 255 random number]: rand () 256) 2. (Linear) interaction with the mouse dynamic linear mapping. (See 3.5 of 2 and 3)