Prepare star fruit (carambolas) by cutting off the edges of the ridges. Remove seeds if you want to do so. Slice in 1/2 inch slices. Combine tapioca and sugar and lightly mix with sliced fruit. If the fruit is very sweet ad 1/4 cup lime juice.
Line a 9-inch pie pan 1 crust. Spread prepared fruit over pastry. Dot with small pieces of butter and sprinkle with nutmeg. Roll the top crust so it will be large enough to make a good seal. Cut gashes to allow steam to escape. Or cut out stars.
Bake about 35 minutes, or until pastry is golden brown.