The platypus flag in panel 5 is a reference to Skewed Reality!
Barbara and Chester
Platypies, both straight
There aren't many platypi in the world, and the increase in inter-species relations have strained the integrity of the species. Thus, The United Platypus Coalition practice arranged marriages, selectively breeding platypi together in accordance to the best combination of genes. Polygamy is also put to work to help create as many children as possible.
Some critics, mainly dingoes I guess, claim that the Coalition is trying to create a genetic super-breed in an attempt to, one day, take over the world. The Coalition refuses to comment on the matter.
Barb and Chester here are arranged to be married about five years from now. They were chosen because both their parents are developed mathematicians, and the Barbara/Chester spawn will certainly not be a perfect architect for the new world order, if that's what you're thinking.