Or in case you wanted a sun-like movement

var offset = 500;//sun offset from level origin
var sun_tilt;

action fake_sun
{
while(1)
{
vec_set(my.x, nullvector);//place at a levels origin
vec_add(my.x, vector(offset,0,0));//add offset
vec_rotate(my.x, vector(0, sun_tilt, 0);
sun_tilt+=5*time;//increase sun tilt
wait(1);
}
}