The Postimpressionistic “Letterboxes” cartoon.

OK YOU DOG LOVERS OUT THERE…
I have a new cartoon in Stock Dogs magazine…
“Red and Blue” – the adventures of a red kelpie and a blue healer!

The first one is based on a Fab Bush Pigs strip.
Here’s a sample.
I’ll send out the full cartoon when it’s published, soon.
Can anyone guess the punchline?
Cmon…easy!