This flashing allegory with 555 integrated circuits was found in the Radio Electronics Experimenter magazine from 1989. It is a simple circuit to assemble.
This is a high efficiency version with the MC723 which is the Motorola version for this well-known...
This circuit was found in the March 1997 Electronics Now magazine. It uses a common analog...
This circuit is from an 80's documentation. It makes use of two SCRs with current capacity...