In the 2x2 resolution (which can't support all of Braille, but does support the first 10 characters), A, B, C, E, and F are all the recognizable Braille shapes

In the 2x2 resolution (which can't support all of Braille, but does support the first 10 characters), A, B, C, E, and F are all the recognizable Braille shapes for those letters (though in offset positions). At first, it seemed like an Easter egg, but it's probably just a natural happenstance of two people centuries apart deciding to represent the first ten letters of the alphabet in a 2x2 grid with a general idea to use fewer dots at the start than at the end.