=John McCarthy ...prescribes a sequence of radio signals...
What would be a good initial attention-getter? What they call "attract mode" in arcade games? The primes are often suggested, but where to stop and repeat is a puzzler. I think it should be a distinctive finite sequence. How about cycling (the negatives of) the Heegner numbers? ||: 1, 2, 3, 7, 11, 19, 43, 67, 163 :||? Precariously tilting the math/fun ratio: Of course if the ETs are Militant Pythagoreans it might only provoke them to dispatch berserkers to quash our secret blabbing. My son and I while away gate holds proposing wrong-headed interpretations of the supposedly "universal" pictorial airplane emergency cards ("Caution! Beware this flying arrow!"). Similarly:
=Daniel Asimov A few simple equations like | + | = || and || + ||| = ||||| should reveal the meanings of + and =.
optimistically assumes Murphy's Law isn't universal! More likely, "If anything can be misinterpreted, it will be." For example those graphics are equally true equations if we interpret "+" as equal-to and "=" as subtraction (with opposite our conventional handedness). Or, worse, "+" as multiplication and "=" as unequal-to... Perhaps the ETs find it grossly offensive to baldly state facts, preferring a delicate silhouette chiaroscuroed by non-facts? Thus trying their elder-race politeness to find interpretations for which all our equations are UNtrue? But actually the ETs have already gone home, based on early telescopic reconnaissance. Why, just yesterday I was admiring the huge ad (something about two services for the price of one) on the side of an SBC (telco) truck which said (in a meter-high font, easily visible from orbit) 1 + 1 = 1 Doubtless, the berserkers are coming to quash our insidious intergalactic mathematical disinformation campaign... --Tixe Ylno