Many of us like sketching, doodling, scribbling or whatevering depending on the end product -- a neatly finished one, or left as is, though making sense with some sense of semblance even in its raw form.
With the advent of smartphones, things have become easier to have apps to aid, when you have some time and inclination. A picture if is worth a thousand words, but the smarter ones these days use a thousand words to tell AI what to draw though!
The above is one such, done on the phone with no definite idea when started. The kind that begins somewhere in the middle, and depending on the blank canvas around, gets shaped into something finally, mainly when not done in one sitting, trying out various brush effects just to get the hang of it.
Having tried different applications, don't recall which got used, but my guess is Markers by ng-labs on Android.