I will give an explicit description of a Calabi-Yau threefold which becomes, for certain values of the parameter, an attractor variety of rank 2. The periods of this variety have remarkable number-theoretic properties which will be reviewed. This reports on joint work with X de la Ossa, Mohamed Elmi and Duco van Straten, and earlier work with Xenia de la Ossa and Duco van Straten.