We have hosted a group of 14 pupils from different high schools from Olot and Besalú, aged from 15 to 18 years, and we have proposed to them seven projects to investigate during the day. The students have signed up for the project that they preferred, and finandally they have formed four working groups.

The first group has experimented with drawings, to discover which property is shared by those drawings that can be drawn with a single stroke, without lifting the pencil from the paper.

The second group has studied the error detecting/correcting codes, which are nowadays crucial for DVD and BluRay, as well as for WiFi networks.

The third group has analised a combinatorial game that can be applied to divide the rent of a three-room flat among three people in such a way that everyone is content with the resulting distribution.

And finally, the fourth group has studied how to calculate the area of a polygon drawn on a grid, simply by counting the points of the grid lying inside the polygon and those lying on the border.

After spending all day working on their projects -save for a lunch break on the sunny terrace- they have prepared posters to explain the results of their findings, which they have been able to present to the rest of participants.