Untested, but here you go:
rem setup screen
sync on
sync rate 60
backdrop on
color backdrop 0
hide mouse
rem main loop
do
rem draw the circle
posx=320
posy=240
radius=50
angle=80
draw_circle(posx,posy,radius,angle)
rem refresh screen
sync
rem end of main loop
loop
rem functions --------------------
function draw_circle(posx,posy,radius,angle)
rem locals
local t as word
local x as integer
local y as integer
local oldx as integer
local oldy as integer
rem calculate first positions
x=posx
y=posy+radius
rem draw circle
for t=1 to angle
oldx=x
oldy=y
x=posx+(cos(t)*radius)
y=posy+(sin(t)*raduis)
line oldx,oldy,x,y
next t
endfunction
TheComet
