Conversation

For years, Mattel marketed a Barbie typewriter. When they switched from mechanical to electronic typewriters, they chose to license from a Slovenian manufacturer, Mehano, who readily supplied their E-115 (and later 116-118) model.

But these typewriters had a secret: hold SHIFT and LOCK, and press one of the first four keys on the first row, and the typewriter switches into substitution-cipher mode, encoding whatever you type:

http://www.cryptomuseum.com/crypto/mehano/barbie/