Pencil-ruler.

I drew this interesting pencil-ruler over subway sketch from my trip to Manhattan. This pencil is roller-ruler from 0 to 36 inches. You roll it's round wheel-head and it counts inches by moving little mark in the middle of dent with markings on pencil's body. Isn't cool?
 I used different Kuretake pen brushes for it, amazed by versatility, more to explore. Finally I got long desired Kuretake Brushables! Yes!