Rubik's revenge. (evaluation) Brian J. Murphy.

Having conquered all the known world, the irresistible wave of cube puzzles has invaded the realm of micro-computing in the form of David Bar-stow's The Programmable Cube which, like its real-life counterparts, is much more complex than it seems at first glance.

For casual cubesters and those with short interest spans, the program would appear to be a poor investment in comparison with a real cube puzzle, which costs only a few bucks. But for those who like doing mental calisthenics, who have developed cube solving theories, or who would like a beginner's level introduction to programming principles, The Programmable Cube offers many delights.

When you boot up the disk, you see three faces of a cube. Facing you are the red stripped, green, and blue sides. mirror images reveal the colors of the sides facing away from the viewer: gold, violet, and orange. Like the original cube, The Programmable Cube has nine smaller cubies per side. A system of simple commands--F moves the front side one quarter turn clockwise, U moves the upper side a quarter turn counter-clockwise--enables the user to manipulate the cube in exactly the same way as a real puzzle. In fact, using this set of 18 commands, you can scramble your cube and attempt to solve it with about the same ease as the real cube.

If you like, you can bevel the entire cube around using a set of nine rotation commands. This means that the faces the computer recognizes as the front, back, right, and left, will change, adding an extra challenge in solving. At this point you can also combine commands in a series before you press Return to execute, giving you the opportunity to relax and just watch the cube twist and spin itself.

Once you have mastered the simple moves, the program allows you to Scramble the cube to your heart's content. You specify the number of twists the cube will be given, the computer figures it out without actually showing you the moves, and the jumbled result is displayed a few seconds later on screen.

Scrambling with three or four turns might not be too big a challenge for an experienced cube solver, even given the necessity of becoming used to the simulation, but if you pick a factor of 30 or 100 turns for your Scramble you may be in trouble. There are two ways out. One is to Reset the puzzle, which simply rearranges the cubies into their original positions.

The other way is to use the Solver program, which will undertake to do the job itself. Sitting back you can enjoy the spectacle of a cube apparently struggling to solve itself. Ah, sweet revenge...

Should you still want to do the job yourself, but hate having to enter all those moves into the computer, the game comes with an easy to follow instruction booklet which leads you, step by step, though a special programming language you can use to write your own cube-solving programs. Programming A Solution

Barstow's game allows you to take those theories of yours, those formulas, those hunches, put them in program form and turn them loose on the cube until--one hopes--a solution is derived. This simple programming system allows you to define moves individually and in series. You can write a program to recognize when all the cubies are in their proper position, and to exit once that is accomplished.

About the only real barriers to the process of learning to program with The Programmable Cube are getting used to the two dimensionality of the cube and learning the names of the 26 cubies, which are named not by the colors on the hi-res screen but their up, down, right, left, back, and front locations. Sometimes it is hard to remember that the violet, blue, and gold cubie that is so far away from home is really the FDL--Front, Down, Left. It helps to make a chart of which colors correspond to which directions.

The author told us that he developed the program not only becauses he was interested in the cube as a puzzle which could be adapted to computers, but also because it would make a useful tool with which to analyze cube algorithms and to teach elementary concepts of programming.

The Programmable Cube certainly achieves these goals, and in an amusing, entertaining way. The hi-res graphics are pleasing to the eye, although the animation is unexciting.

Commands are executed quickly, but it takes a second or two for the prompt to reappear, surprisingly slow for a program written in Pascal. By the way, don't panic: The Programmable Cube will load its own Pascal into your Apple without you having to buy Apple Pascal.

You may want to invest in a 16K RAM expansion board, however, because The Programmable Cube comes in two versions, 48K and 64K. The programs use up a lot of memory when you write your own solver, and in the 48K version you have room for just one moderately long solver program. In 64K you have enough free memory to load one long or two compact solvers.

So, if you don't have VisiCalc or a word processor but still have the itch to upgrade to 64K just for the fun of it, here is the excuse you have been waiting for. Tell your missus (or mister) that you have become a cubeaholic, and you must have a 16K expansion board to sate your ungodly appetite.

Who knows, maybe after you have fooled around with The Programmable Cube long enough, you'll become a cubeaholic for real.

Products: Metacomet Software The Programmable Cube (video game)