Lines and brush strokes

You can draw out or create a new shape of any kind, set the fill/outline to your liking, then click the disk icon in the artistic media brush toolbar at the top which you will see while you have that tool active to save as a custom brush. Now in the "category" drop menu of that same toolbar, there is a custom brush area. In there is your new brush. Select it and you will continue to paint in whichever way that brush was saved.