The Reversible or Double-Sided Cross Stitch is used when the Cross-Stitching on a piece is to be viewed on both sides of the fabric, as in table linens.

Whereas the regular Cross Stitch is sewn in two passes, the Reversible Cross Stitch is sewn in four. As you can see from the diagrams below, the stitching on the reverse side of the fabric forms crosses.

Note that, unlike the regular Cross Stitch, this variation alternates the direction of the stitch on top; i.e. half the stitches have the top stitch slanting one direction and half the other. Therefore, this stitch is not suitable for Counted Cross Stitch, or other embroidery where the cross is very small.