A typewriter mystery game was a specific type of typewriter art popular in the mid-20th century.

A typewriter owner would be presented with a set of instructions: press a key this many times, press another key, move on to the next line. Upon finishing the typing, a picture would emerge on the page. First lines of a simple typewriter mystery could look like this:

[1] 2 X, 3 spaces, 2 X, 1 space, 2 X, 3 spaces, 2 X, 2 spaces, 2 X
[2] 2 X, 2 spaces, 7 X, 2 spaces, 2 X, 2 spaces, 2 X              
[3] 2 X, 3 spaces, 5 X, 3 spaces, 2 X, 2 spaces, 2 X              
[4] 2 X, 5 spaces, 1 X, 6 spaces, 4 X                             

XX   XX XX   XX  XX
XX  XXXXXXX  XX  XX
XX   XXXXX   XX  XX
XX     X      XXXX

Typewriter mystery games were published in magazines (such as Woman's Realm^[1] and The Journal of Business Education^[2]), and collected in separate books.^[3][4][5] The “mystery” in the name refers to the fact that a visual result of the instructions would sometimes be presented on a different page, in the following issue of the magazine, or withheld altogether, making typing the only immediate way to discover the picture.

The end result of a typewriter mystery game would be a picture similar to the later ASCII art,^[6] except it would often use overtyping – making several passes over the same line,^[1] unavailable or difficult on computer screens. The photo would often be a portrait of a person^[1] or an animal.

• 50 Typing Picture Projects by Winnifred Nichols (1980)
• Bob Neill’s Book of Typewriter Art (1982)
• Bob Neill’s Second Book of Typewriter Art (1984)
• Typewriter Mystery Games by Julius Nelson (1951–1979, one example)
• The 1956 book Fun with your typewriter is similar in that it contains many typewritten graphic elements with proper instructions on how to type them (they are not, however, mysteries).