これだけのプログラムでbballが描けます。
#include "bla_easy.h"
int col[8] = { 0x000000, 0xff0000, 0x00ff00, 0xffff00, 0x0000ff, 0xff00ff, 0x00ffff, 0xffffff };
struct aPoint {
    int x, y;
} p[16] = {
    { 196, 100 }, { 187,  61 }, { 164,  29 }, { 129,   9 }, {  90,   5 },
    {  53,  17 }, {  23,  44 }, {   7,  81 }, {   7, 119 }, {  23, 156 },
    {  53, 183 }, {  90, 195 }, { 129, 191 }, { 164, 171 }, { 187, 139 },
    { 196, 100 }
};
int main()
{
    Window *win = openWin(200, 200, "bball");
    setMode(win, MODE_OR);
    int i, j, c;
    for (i = 0; i < 15; i++) {
        for (j = 0; j < 16; j++) {
            c = i - j + 8;
            if (c <= 0)
                c = 1 - c;
            if (c <= 7)
                drawLineEx(win, p[i].x, p[i].y, p[j].x, p[j].y, col[c]);
        }
    }
    end();
}