To finish the assigned shape, firstly I need a pencil. (The pencil sharpener is much worse to use than knife)
I need to make sure where the center is.
Then I need to fix the wood.
And I need to grill some holes to fix the ruler.
When I tried the first time, I forgot to combine the ruler with the router, so I made it really awful.
Then I fixed them together and I got the shape I want.
When making the line, I drew two lines and tried making their distance equal the radius of the circle ruler. But when I fixed the ruler, I found it not exact, and it was hard for me to move the ruler and fix it again.
So the line I cut is disgusting… I hope I can control the screw better next time.