Here is a two parter for you. Mostly to reinforce that you can build something quite interesting from small chunks of time, as small chunks gradually build up to something much more significant and complex.
Use the below image to create a portrait that is intermingling with nature.
It can be a straight copy of the below image, or you could utilize a different piece of plant, or you could use a different portrait (maybe yourself?!).
Note the media - ball point pen. You can do this, or not. It's up to you.
You might sketch out in pencil one day and add ink/shading the next, or you might go straight to ink and get it as close as possible.
Remember - esp if you are going straight to ink, it isn't about getting as much done in one sitting as possible, but paying attention to the character of the work that you are doing.