CLS
SCREEN 12
WINDOW (0, 0)-(640, 480)
stars = 50
DIM x(stars), y(stars), z(stars), xe(stars), ye(stars)
RANDOMIZE TIMER
FOR i = 1 TO stars
x(i) = INT(RND * 200)
y(i) = INT(RND * 200)
z(i) = INT(RND * 200)
NEXT i
xc = 320
yc = 240
x = 200
y = 100
z = 100
gr = 200

GOTO st
back:
st:
FOR i = 1 TO stars
PRESET (xe(i), ye(i))
NEXT i
FOR i = 1 TO stars
x(i) = x(i) + 5
dy = y(i) - y
r = x(i) - x
IF r = 0 THEN r = 1
tng = dy / r
dye = tng * gr

dh = z(i) - z
r2 = (dy ^ 2 + r ^ 2) ^ (1 / 2)
tng2 = dh / r2
dze = tng2 * ((gr ^ 2 + dye ^ 2) ^ (1 / 2))

xe(i) = xc + dye
ye(i) = yc + dze
g:
IF r < 0 THEN PSET (xe(i), ye(i))

IF r > 0 THEN x(i) = 0
NEXT i

GOTO back
END