Nicely done. My attempts at plarn crochet were less than satisfactory and I've yet to try knitting the stuff. I love your mat. It's enough to make me want to give it another go. When I finish a project I feel like something's missing, there's nothing to grab without much thought, so I have to find a new one to replace it. I need to fill the hole. Maybe that's what you mean?
I should never overestimate my basic arithmetic skills.