Very interesting article. Actually I don't understand why no-one came up with a EM interface for P-Roc, or just a simple generic EM to SS boardset. That way you can leave out the bottom board of relais and just use the coils and switches on an EM playfield. You can easily improve the rules as well. Might as well be a stripped down version of P-Roc boards since less parts are involved. It could save a lot of EMs from the dumpster.