Thank you very much for your so nice comments, George, Kate, Robin, Lizzy, Clydeine, Lexy, Marie, Johanne, Karen, AJ and Trish!
They made my day, too
Madeleine, thanks! Yes I used the Molotow pen, but only for the little dandelion seeds, the other white parts are with colored pencil. The Molotow is useful and you can buy additionally a little set with finer tips. But it is a bit dangereous, because sometimes it drops and suddenly you have instead of a fine white point or line a thick white drop on the paper
But fortunately it can be removed rather well and covered again with colored pencils.