This object has been drawn and printed by students aged 14-15 of the 1 EPAL Chanion Secondary School. The activity has been carried out within the Erasmus+ project PRINT STEM www.printstemproject.eu. and co-funded by the Italian National Agency INDIRE. We used this model in order to enable students to understand the geometric interpretation of the Pythagorean theorem. Also after the students constructed it at 3d printer, they could see and catch the proof of the Pythagorean theorem in their hands