HyperTIES had a feature that you could click or press and hold on the page background, and it would blink or highlight ALL of the links on the page, either by inverting the brightness of text buttons, or by popping up all the cookie-cut-out picture targets at the same time.

Arbitrarily-shaped graphical targets cannot be self-naming the way link text is. An image with hidden targets is a guessing game. The 1991 paper's answer was pop-out highlighting: offset the object, drop a shadow, and let the slight movement catch the eye.

Then: when people sweep an image looking for targets, or click in a non-target area, highlight them all.

A failed click is not an error. It is a request for the map. That is how Sun Founders Big Heads pops all three heads at once.