Pictures or Figures can be understood very quickly. The global meaning or the gist of a picture can generally be attained in an easy and rapid way, in as little as 300 ms (Peeck 1993:228). This "gives the illusion of full understanding" and so "students often deal with illustrations in a superficial and inadequate way" (Peeck 1993:228). When textbooks become heavily illustrated, this effect of pictures can distract from learning. The presented invention is based on the simple fact stated as above.