I dug out one of my Lamy fountain pens, which had a black ink cartridge in it. I swapped the black for green, and drew this on some bristol board.
From time to time I dipped the nib in the black ink so I had some gradients and variation in the drawing.
It was fun to do. Also, it’s been a while since I drew with pen on paper; most of my work of late has been digital drawing, with the occasional pencil/pen sketch on paper.