Here is an approximation to a Schwarz P surface that I designed for the InforMath project funded by the National Science Foundation (DRL-1323587). The InforMath project (http://informalmathematics.org/) is a partnership between San Diego State University and several museums at the Balboa Park, including the Reuben H. Fleet Science Center (http://www.rhfleet.org/). A Schwarz P surface is a triply periodic minimal surface. The approximation is given by all points (x,y,z) such that cos(x)+cos(y)+cos(z)=0.
These models are designed to join together using small magnets. There are two options for the print files, ones with small holes for the magnets and ones without.
Also prints on a uPrint SE printer with rafts and supports.
Several copies of the surface can be held together by 3mm (diameter) x 3mm (height) cylindrical rare earth magnets (http://www.gaussboys.com/store/index.php/magnet-shapes/cylinders/c0303.html).
The magnets should fit snugly, and I didn't need any glue. If you do, you could try using a little JB Weld epoxy just in case. I suspect that you could also use superglue. I highly recommend printing DesignByNumber's magnet insertion tools (http://www.thingiverse.com/thing:436565) to help seat the magnets into the little holes.
You can alternate the magnets around the rim of the surface. The rim on the opposite face should have the opposite orientation on corresponding magnets.