SLOG by the end of the 3rd week

This week we continued  learning about mathematical expressions, like conjunction, disjunction, negation and so on. I have already learned it in high school, to my surprise, it is getting hard than I imagine. I used to draw Venn Graphs for the expressions which are complicated and abstract, and it is still useful while I learn this part at a different sight angle.

Actually, I kinda like the content of class in this morning, a interesting puzzle of folding a piece of strip. I like to find the regular pattern of it, and this one was not hard for me. I used arrows to represent ups and downs directly. I was wondering whether there were more than one outcome as we fold it irregularly before I started, a terrible picture of numbers and arrows appeared in my head, and that was too complicated. Followed the steps and I recorded the vertex of the creases point by arrows. First that were odd numbers of creases points each time, by formula (2^n-1), when n is the times of folding. Then I found each time the middle arrow which was always down, and that made me think whether it could be symmetrically to spread the arrows(the symmetric I said was not a standard mathematical symmetric). Next I found the arrows in the previous folding could be carry down, and with filling ups and downs at each gap of two arrows it came out the one we just recorded. Actually I tried four foldings and I was pretty sure my solutions was correct.