Monday Cartoon Day.
Before landing the job of his lifetime at Mad, Mort Drucker worked as a comic book artist for several companies. For DC, he seems to have done his first serious work, as the producer of their filler 'fact' pages in several titles. Some of these may even have beendone while he was still on staff as a retoucher. There were more people doing this sort of thing, but I am pretty sure these are all by Mort.