Brown also acknowledges significant debts to Jack Jackson's historical comics, Hergé's "The Adventures of Tintin", and the extremely exaggerated style of Larry Gonick's "Cartoon History of the Universe". He says he referred to Jack Hamm's "How to Draw Animals" when drawing the horses that appear frequently throughout the book, which were rendered running with their legs splayed, as an artist may have depicted them in the days before the influence of Eadweard Muybridge's photographs of bodies in motion. Brown drew each of the 1325 panels separately on watercolour paper on a block of wood he placed on his lap in lieu of a drawing table, which allowed him seamlessly to rearrange, insert, and delete panels as he saw fit. The drawings were finished using both a thin ink brush (no larger than size 0) and dip pen with a Hunt 102 nib and black ink.