Richard, only you my friend! Yes, I'm proud to say that I tend to think outside the "condom"!

For those of you wondering why I made them square
1) It's easier then trying to keep it round
2) Most of the cat condoms I have bought are rectangular
3) They fit the couch cushions better and cover more space.

Same instructions as the round ones but I do round off the corners so it's easier to sew. When I stuff the tube I put a wad of stuffing in and use my yard stick to push it to the back of the roll.
The open end one is made the same way but with the tube only sewn to three sides.
Also, when I stuffed the actual bed part I tufted the bottom so that when they get washed the stuffing won't shift and ball up.

There are no bounderies or set rules when making these. You are free to make them any size or shape you want. Just go for it and have fun!