Reverse: The Classic Computer Number Game

This is an adaptation of game that was circulating on computer systems in the early 1970s, called Reverse. I give some background below, but if you want to get started on trying the game, here are some instructions.

How to Play Reverse

Reverse is simple to play, but difficult to master. You start with a string of digits and the goal is to rearrange them so that they are in ascending order. You can only rearrange the digits by reversing their order from the left.

For example, if I start with the string 43215, I would reverse the first four digits by clicking on the “1”, resulting in 12345. To try a simple example like this, reduce the number of reverses to one (using the arrow buttons on the bottom). With this setting, you will only be presented with sequences that have been reversed one time. Once you’ve solved a few such sequences, you can increase the challenge by increasing number of reverses that are used to generate the sequence. You can also adjust the difficulty by changing the number of digits in the sequence.

Scoring

Your total score is shown in the upper left corner. You will gain points for every sequence that you successfully rearrange, and the number of points you receive will depend on the number of reverses you use to get it in order.

This is reflected by the Bonus, shown in the upper right corner. The Bonus starts at 100 with every sequence. If you use more reverses to rearrange the sequence than were used to generate it, your bonus will decrease with every additional reverse.

If you’re struggling with a particular sequence and just want to skip it, you can do so by pressing the Skip button. However, you will be charged 100 points. The Reset button will reset the whole game, including the score. Note that changing the number if digits or reverses will also reset the score.

Background

At the same time arcades were filling with ball and paddle games, a different kind of revolution was happening in the world of computer games. Computers were still largely restricted to universities and businesses, but the development of the BASIC programming language in the early '60s made it so that a person could write a simple computer game without much computer expertise.

The 1973 release of 101 BASIC Computer Games was a milestone for game programming, but it would take several years to fully appreciate its significance. At the time of its release, BASIC programmers were all working on mainframe computers or minicomputers, and the audience was relatively small. However, in 1974 the first microcomputer (i.e., PC) was released and the pool of computer programmers expanded rapidly from there. Microcomputers began to pop up in homes around the world and by the end of the decade the book had sold over a million copies.

The games in the compilation are all over the map, including card games (e.g., Poker, Acey Ducey), frivolous guessing games (Animal, Guess), text-based adaptations of sports (Baseball, Basketball), graphical demos (Banner,Bounce), grid-based searches (Battle, Mugwump), simulations ( Hamurabi, Civil War), and many others.

Many of these games have analogs outside of the world of computers and had already existed in one form or another. For example, Awari is just a variation of Mancala and Bagels is similar to the board game Mastermind. However, many were original to computer systems, including Hamurabi, Lunar Lander, and the game demonstrated above, called Reverse.

The original Reverse is credited to Bob Albrecht in 101 BASIC Computer Games. Albrecht was a major player in the early days of personal computers and even one of the founders of The People's Computer Company in 1972.

Differences from the Original

The version of Reverse demonstrated here is not an exact copy of the original (which you can play on an emulator). The most significant difference is the interface. In the original, you would choose where to reverse the digits by typing in the number of digits you want to reverse. Mouse-based interfaces, like the one I use here, wouldn’t become common in home computers until the mid-80s.

Another important difference is that the BASIC version started with a random sequence of digits, rather than a sequence rearranged with a specified number of reverses. This would have resulted in a high initial difficulty, since an arbitrary random sequence is not guaranteed to have any patterns to exploit in finding a solution.