Children under 3 are enthusiastic users of mobile devices and have the ability to emulate a number of the gestures adults use on touch screens, according to the literature on Child-Computer Interaction (CCI). Nevertheless, relatively few studies have focused on the spontaneous interaction of children with screens. The objective of this empirical research is to study unstructured interactions of children under 3 with two apps that permit free drawing and coloring. Observation includes the first gesture used for interaction and the use of on-screen tools (e.g. color palette). Twenty-one participants aged 14 to 33 months (average of 24 months) were recorded playing with free drawing and coloring apps on a tablet using a non-invasive method in a natural context (two nursery schools, one in London and one in Barcelona). Analysis of the data gathered showed that children under 3 adapt their gestures to the content of the apps and suggests that the use of tools may begin from 24 months. Based on those results, the content of an additional 32 apps for drawing and coloring aimed at children from zero, one or two years old were then reviewed. The analysis highlighted the need for more studies on the interaction of young children with apps to foster the development of interactive resources appropriate to a child's age and development.