The Zotmeister

11:48 pm - Puzzle 36: Chromapraxia

In the same way that a phobia is a fear and a philia is a fetish (like my own kosmemophobia and kamiphilia), a praxia is a competency or skill; 'chromapraxia' is the ability to paint, something I decidedly lack. However, it's logic that will get you an image here, not artistic skill.

This puzzle design actually has quite the history, starting with controversy over who created it first. My money is on Non Ishida, who won a design contest with it, inspired by the patterns of lights created by skyscraper windows at night. It became very popular for a period, being the subject of several books, websites, video games, and a still-running regular column in GAMES Magazine. Non certainly appears to have done more for dissemination of the puzzle's popularity; it's accumulated dozens of names, but "Nishiogram" is not one of them and Nonogram is. Other names include Paint by Numbers (the GAMES Magazine title, and the title of its Wikipedia article), Griddler, Tsunami, and Logic Art; the Nikoli name is Edel.

The left is an unsolved Chromapraxia puzzle; the right is its solution. "Si, señor - it is the number two." Zorro the Gay Blade is a genius film that was ahead of its time, but I digress.

Some cells of the grid are to be colored; the objective is to determine which, and what color each is to assume. (The end result is to be interpreted as an image.) The numbers to the left of each row are the lengths of all contiguously monochromatic groups of cells within that row, the left-to-right order of those numbers matching the left-to-right order of the cell groups they refer to as they appear in that row; the numbers above each column are the lengths of all contiguously monochromatic groups of cells within that column, the top-to-bottom order of those numbers matching the top-to-bottom order of the cell groups they refer to as they appear in that column. The color of each number matches the color of the cell group it refers to.

A numbered list of rules probably won't help much, so instead, here's a casual explanation of the sample:

First of all, all the numbers outside the puzzle are black. Both the sample and the full puzzle below are only a single color. So basically, all you have to do is figure out whether any cell of the grid is to be colored black (shaded in) or left blank (I'll put a dot in those to mark them as uncolored).

See how the bottom row of the sample solution has '5' to the left of it? That means there need to be five black cells all in a row to the right of it. Of course, the whole grid is only five cells across, so the whole row is black.

Now look at the center column: it has '1 1 1' above it. This means that it needs three separate black cells - they need to be separate because you'd have a '3' above the column instead if they all ran together. In other words, there needs to be at least one space (uncolored cell) between the first and second cells, and at least one space between the second and third. (Note that if they were different color numbers, they could be right next to each other, but all the numbers here are the same color, so a space is the only thing available for separation.)

The second column from the left reads '1 2'; the '1' is above the '2'. This means that the single black cell must be higher up in the column than the two next to each other. Basically, the order of the numbers matches the order of the groups.

Once you've shaded in the cells needed to make all the numbers outside the grid accurate, you've not only solved the puzzle, but made a picture! For the sample, it's just the digit '2' in my pixelled style - not exactly Picasso, but hey, it's a start.

If you understand the instructions, the sample puzzle is really easy. If you don't, I'll accept the blame and try to make it up to you here:

( How to solve the sample puzzle )

In keeping with the Puzzle Japan theme, this puzzle is monochromatic - all black cells, no other colors, just like the Edel formerly of that website. In Nikoli style, I'll also provide a small hint for the image: "Puzzle champion". I'll still be pretty impressed if you can tell me what it's supposed to be, though. - ZM