On step-2 transforms for simple perfect squared squares

In the context of simple perfect squared squares, a step-k transform is a relation between two squares, of respective orders n and n + k, such that if one of them is known, the other can be found in an elementary way. Many such transforms are known, but only for k = 0 and k = 1. In this paper two different step-2 transforms are constructed. By use of them and one of the authorʹs own special step-0 transforms, two new simple perfect squared squares of order 28 are derived. The diagrams of two 3-clusters of squarings are included. Some open questions are indicated.