In case you're wondering why I have a square flap cut into my grey tube of gouache, it's not because I'm too lazy to open the tube and squeeze some paint out. Long story short, my sweet long-haired cat, Theo, jumped up on my art table and decided to steal my paint. I found it on another floor of the house with tooth marks all over it. All of the little puncture wounds allowed air to penetrate into the tube, thus leaving it hard as a rock. So, I took an exacto knife and cut a flap so that I could still use the paint. I'd prefer wet paint, but I'll work with what I've got!