# Chapter 10: Pattern

You have a grid of squares, which must all be filled in either black or white. Beside each row of the grid are listed, in order, the lengths of the runs of black squares on that row; above each column are listed, in order, the lengths of the runs of black squares in that column. Your aim is to fill in the entire grid black or white.

I first saw this puzzle form around 1995, under the name ‘nonograms’. I've seen it in various places since then, under different names.

Normally, puzzles of this type turn out to be a meaningful picture of something once you've solved them. However, since this version generates the puzzles automatically, they will just look like random groupings of squares. (One user has suggested that this is actually a good thing, since it prevents you from guessing the colour of squares based on the picture, and forces you to use logic instead.) The advantage, though, is that you never run out of them.

## 10.1 Pattern controls

This game is played with the mouse.

Left-click in a square to colour it black. Right-click to colour it white. If you make a mistake, you can middle-click, or hold down Shift while clicking with any button, to colour the square in the default grey (meaning ‘undecided’) again.

You can click and drag with the left or right mouse button to colour a vertical or horizontal line of squares black or white at a time (respectively). If you click and drag with the middle button, or with Shift held down, you can colour a whole rectangle of squares grey.

You can also move around the grid with the cursor keys. Pressing the return key will cycle the current cell through empty, then black, then white, then empty, and the space bar does the same cycle in reverse.

Moving the cursor while holding Control will colour the moved-over squares black. Holding Shift will colour the moved-over squares white, and holding both will colour them grey.

(All the actions described in section 2.1 are also available.)

## 10.2 Pattern parameters

The only options available from the ‘Custom...’ option on the ‘Type’ menu are Width and Height, which are self-explanatory.

[Simon Tatham's Portable Puzzle Collection, version 20231120.08365fb]