Abstract: A protrusion which is removably attachable to an exterior ventral surface of an article of clothing worn by a subject and which causes mild discomfort but no injury to a subject when the subject lies on his back, thereby urging the subject not to lie on his back when asleep.

Abstract: A chordic keyboard including chordic data entry locations corresponding to the five fingers of the human hand and correlation apparatus for correlating a set of chordic data entry location engagement combinations to a set of letters in accordance with a code which is characterized in that available data entry location engagement combinations are arranged in a plurality of groups, the engagement combinations in each group having a predetermined relationship among their fingering patterns, each group being matched with letters forming a recognizable combination of letters, whereby the fingering patterns are readily memorizable.

Abstract: A toy including apparatus for producing a desired sequence of sounds and chordic keyboard apparatus for operating same. The desired sequence of sounds may be human speech, music or any other desired sequence of sounds. In a preferred embodiment of the invention a talking doll is provided.