setscreen ("graphics:vga")
setscreen ("nocursor")
var c, x, y : int
randomize
const centerx := maxx div 2
const centery := maxy div 2
loop
    for radius : 1 .. 400
        randint (c, 0, 1)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 2)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 3)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 4)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 5)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 6)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 7)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 8)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 9)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 10)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 11)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 12)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 13)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 14)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 15)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 14)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 13)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 12)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 11)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 10)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 9)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 8)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 7)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 6)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 5)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 4)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 3)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
    for radius : 1 .. 400
        randint (c, 0, 2)
        drawoval (centerx, centery, radius, radius, c)
        delay (5)
    end for
end loop