OK. I got to the cube mapping type. It was only when I saved (or used "filled") that I saw the cross I was looking for.
Next question: it is now four parts wide, and the same width for three in height. But it was a square. And there is no exact mathematical relationship between one fourth and one third. How do I get a cross of  squares? I can approximate by reducing the height, but that won't give me squares.

BTW: thanks for replying. I now already have a cross. And I will experiment further.