Contributors photograph or scan pages of their own handwriting: lecture notes, problem sets with the work shown, derivations, diagrams and annotated sketches, in whatever language and script they study in, reviewed for legibility and task fit. Expect the variation of real notebooks, not a scanning booth, from a global base strongest in Southeast Asia, the United States and Europe, in Latin and non-Latin scripts. There are no transcriptions; the worked-solution pages are a rare record of how people lay out intermediate reasoning on paper. Nearly every public handwriting corpus of any size excludes commercial training (IAM, MathWriting, CROHME); this one does not.