A kit for building a module for a pet comprises two bases and at least three wall panels. Each base comprises a base body extending along a first plane, a base contour wall extending substantially perpendicular to the first plane along its contour and a base secondary wall extending substantially parallel to the base contour wall thereby defining an anchoring space therebetween. Each wall panel comprises a panel body and a panel secondary wall substantially parallel to the panel body for insertion into the anchoring space between the base secondary wall and the base contour wall.
