[Learn to Draw Dotted Lines on a Chalkboard || Learn Quick] (Viewer #568,398)

He finally explains the technique at about 2:37, so skip ahead if you get bored, although there is some entertainment value in watching him both puzzle it out and revel in his discovery.

I was successfully doing dotty lines with about 15 seconds’ practice, so if you use chalkboards at all, it’s worth the effort.