Back when I was trying to make it as a self-employed illustrator, in the pre-TMNT years, one of the ideas I had for making money was to create, print and try to sell a variety of cards for different occasions. For several years, I employed my used book store as the primary venue for this attempt... which didn't really work -- I think I sold a few dozen cards. Not a terribly successful venture, but it was fun.
I am pretty sure these two designs were done for this purpose, though it is also possible that I drew them for friends' or family members' birthdays. Or I could have used the art for both things. In any event, they were enjoyable to draw. -- PL