// Copyright (c) 1995, Masanao Izumo

#define WINSIZ 500
#define N      32

function draw()
{
    local i, k;

    for(i = 1; i < N/2; i++)
    {
	for(k = 0; k < N; k++)
	    gline(cos((2 * M_PI / N) * k),      sin((2 * M_PI / N) * k),
		  cos((2 * M_PI / N) * (k + i)),sin((2 * M_PI / N) * (k + i)));
	sleep(0.05);
    }
}

gopen(WINSIZ, WINSIZ, 0, "black");
gwindow(-1, -1, 1, 1);
color_list = new("red", "green", "blue", "yellow", "cyan");

while(cdr(color_list) != NIL)
{
    gpen(car(color_list));
    draw();
    gpen("black");
    draw();
    color_list = cdr(color_list);
}
gpen(car(color_list));
draw();

gpause();