>Anyway, you see this "beating" effect of the 2 grids cancelling >and reinforcing difference patterns (if i remember my yr 11 physics, >Newton's rings?!). It's the moire' (an acute accent, not an apostrophe) effect. Remember that thing to the right of Mr. Spock's station on the bridge? Terry Bowman, KA4HJH "The Mac Doctor" ICQ: 45652354