Bill wrote:
Does anyone know a good and simple way to have 4 LEDs blink in a random
pattern
I need some parameters. How random? Is the frequency of LED flashing to
be low enough that it doesn't look like a blur to the eye?

Probably the best simple method, if you don't have a uP development
setup, is to have a 4-bit counter feeding the 4 LEDs (via current
buffers probably), and a high frequency (1MHz?) clock feeding it via a
gate so that it gets clocked for roughly 1mS and then sits with the
4-bit output reached for roughly 50mS, then counts again. So long as
the counting time is varying slightly (a 555 timer might be variable
enough by itself, but I'd suggest adding some simple radio output into
the timing - ask me if you need a circuit).

Mark.