sketchpad
/ˈskɛtʃˌpæd/Definitions
1. noun
A book or pad of paper used for making quick drawings or sketches, often used as a tool for brainstorming and idea generation.
“She used a sketchpad to rough out her ideas for the new design.”
2. verb
To make a quick sketch or drawing, especially one that is not intended to be a finished work of art.
“He sketched out the scene in his mind, trying to capture its essence.”