Thank you so much Melanie

What is more, it works perfectly ! - assembled 1st time, with no errors.

At one stage, I did actually think about using an incremental counter, with a Gosub/Return statement in the switch monitoring loop, to check the value of the counter and take appropiate action.

However, the problem still remained of having to 'toggle' the O/P's on & off for 250ms each (and the huge delays using the combined TOGGLE & PULSOUT commands).

Your solution is very clever - I guess simlilar to 'multiplexing' a multi-digit 7-segment LED display, when only 1 digit is on at any one time, - 'persistance of vision' fools your brain into thinking they are all on at once !

I'll let you know how I get on 'tweaking' the code & post the results here.

Thanks again