листья Skeletonization of leaves - the process simple, but requires patience and accuracy. All you need is: leaves (better to collect the autumn, then they are more dense), baking soda and food coloring.
Sheets for the identification of different leaves, animal tracks and flying birds. Available as poster oder print at Posterlounge and as postcards at Artflakes. Also part of the "Lily Lux Notizbuch" (.