A graph is Bk-VPG when it has an intersection representation by paths in a rectangular grid with at most k bends (turns). It is known that all planar graphs are B3-VPG and this was conjectured to be tight. We disprove this conjecture by showing that all planar graphs are B2-VPG. We also show that the 4-connected planar graphs constitute a subclass of the intersection graphs of Z-shapes (i.e., a...

Currently, there are large collections of clip-art vector drawings from which users can select the desired figures to insert in their documents. However, to locate a particular drawing among thousands is not easy. Although there are some solutions for drawing retrieval, almost all of them are designed to retrieve simple and not complex drawings as for instance clip-arts. In our prior work we pr...

New computerized techniques allow the precise measurement of psychomotor retardation in patients with a major depressive episode (MDE). One such technique is the analysis of writing and drawing behaviour during figure copying tasks. In the present study, 22 inpatients with an MDE were compared to 22 normal controls. Three tasks were used: the drawing of lines and simple figures, the copying of ...

Visual articulation of compound figures is more fragmentary in children whereas it is more integrated in adults. In this experiment, eye movement of children during visual exploration of test figures was recorded under the hypothesis that the fragmentary articulation should be related to the same fragmentary character of the eye movement. The subjects were 20 children of 4-, 5- and 6-years old ...

Individuals with Williams syndrome (WS) produce drawings that are disorganised, likely due to an inability to replicate numerous spatial relations between parts. This study attempted to circumvent these drawing deficits in WS when copying complex combinations of one, two and three shapes. Drawing decisions were reduced by introducing a number of facilitators, for example, by using distinct colo...

The drawing figures are widely managed as an ideal instrument for self-expression. HFD test (Human Figure Drawing) is an abbreviated test which was developed with the aim to evaluate various psychological states, especially assessing the psychic status including psychiatric illness and personality state. Thus, the reliance on the drawings must be proven that it has no bias due to cognitive diff...

This paper focuses on the collaborative learning of mathematics in which learners effectively acquire knowledge of common exercises through discussion with other learners. During collaborative learning, learners sometimes cannot solve exercises successfully, because they cannot derive answers by themselves or they hesitate to propose answers through discussion. To cope with such situations, thi...

Nowadays only digital figures are accepted by the most important journals of taxonomy. These may be produced by scanning conventional drawings, made with high precision technical ink-pens, which normally use capillary cartridge and various line widths. Digital drawing techniques that use vector graphics, have already been described in literature to support scientists in drawing figures and plat...