1.按字母“Y”画一个用点组成的圆；

2.按字母“S”画一个用不同颜色填充的三角形；

3.按字母“Z”画一个用不同颜色填充且带有边框图案的矩形；

4.按“q”键退出

-1. According to the letter "Y" draw a circle with points　

2. According to the letter "S" draw a different color filled triangle　

3. According to the letter "Z" draw a filled with different colors and patterns with a rectangular frame　

4. By "q" key to exit