This is a detail of thumbnail sketches when I reworked my visual references for composition and colour tryouts. If you look at an earlier image posted, you may possibly recognise one of the plants sketched at Cocklespit beach.
I regularly use the technique of ‘thumbnails’, as they are small, (for me approximately 5.0cm x 6-8.0cm), and take very little time. This helps me to generate and make visual, a number of ideas on the same page ready for reworking, in this instance, with acrylic and indian ink.