此程序可实现：在一个可视化界面中随机生成3种safe－colour（不显示白色）；用户可将颜色自由添加至4种类似的色族中；程序最后显示出用户添加颜色的分布。-this procedure can be achieved : in a visual interface randomly generated three kinds of safe-color (not shown white); users will be able to freely add color to 4 color si