The orientation is determined by the seed crystal. You can choose whatever you want. There will of course be long and skinny pieces. These will be much easier

The orientation is determined by the seed crystal. You can choose whatever you want. There will of course be long and skinny pieces. These will be much easier to recycle than the unused portions around the edge of a circular wafer; they need not leave the facility that cuts the wafers. The end result is rectangles of a standard size in one dimension and varying side in the other dimension.