module chamferedCube(size = [1, 1, 1], chamfer = 1) {
  ep = 0.01;
  difference() {
    cube(size);

    for (i = [0:3]) {
      // X-axis
      translate([-ep, size[1] * floor(i/2), size[2] * (i%2) - chamfer])
      rotate([45, 0, 0]) cube([size[0] + 2*ep, 1.414*chamfer, 1.414*chamfer]);

      // Y-axis
      translate([size[0] * floor(i/2) - chamfer, -ep, size[2] * (i%2)])
      rotate([0, 45, 0]) cube([1.414*chamfer, size[1] + 2*ep, 1.414*chamfer]);

      // Z-axis
      translate([size[0] * floor(i/2), size[1] * (i%2) - chamfer, -ep])
      rotate([0, 0, 45]) cube([1.414*chamfer, 1.414*chamfer, size[2] + 2*ep]);
    }
  }
}