Playing cards could be split and inside a portion of a map. All 52 plus jokers could be laid out to make a map of Germany.

There were brothers that before the war were HAMs. They had designed a transmitter/receiver that used the same parts for both, just a switch was thrown to alter the circuit from transmit to receive. It used a single miniature tube. They had made up a model name for it.

The brother in the prison camp wrote to his Uncle Samuel in Washington and that his brother be contacted to get him what he needed. Somehow someone in the Post Office caught on to the address, and routed the letter to the War Department, and it eventually ended up at Mis-X. They contacted the brother who knew exactly what was wanted. He showed them how to make up a kit of parts and schematic.

The kits were put in hollow aluminum spheres that screwed together, and top company people at Spaulding stayed after hours and stitched coverings on them to look like baseballs. These were slipped into the prison camp as recreational goods.

And that is how 2-way radio was established with the prison camps.