XOj in monochrome

This idea in this page is presently just a suggestion. It is not, at present, part of OLPC official policy and, indeed, may never be. Please develop and discuss the idea and, if thought worth implementing, please implement it.

On several of the slides in the illustration on the http://www.laptop.org/laptop/interface/demo.shtml page there are a number of XOj shown in various colours.

Some children may find it difficult or impossible to distinguish some of the colours from some others of the colours.

There is a method, dating back to the 1600s, for depicting colours in black and white illustrations. It was originally developed for displaying diagrams of coats of arms in printed books about heraldry. That being in the days before colour printing technology was introduced. It is known as the Petra Sancta method.

The present suggestion is that each XO could be, as an option, displayed with an accompanying block of chunky pixels in dark chunks and light chunks in a five chunky pixels wide by five chunky pixels high block. Each chunky pixel could be one, two, three or more pixels wide by one, two, three or more pixels high depending upon the display situation.

The designs of the particular five chunky pixels by five chunky pixels symbol would be based on the line directions used for the Petra Sancta system.

Red would be three dark vertical lines separated by two light vertical lines. A total of fifteen dark chunky pixels out of twenty-five.

Blue would be three dark horizontal lines separated by two light horizontal lines. A total of fifteen dark chunky pixels out of twenty-five.

Yellow would be nine dark chunky pixels, placed non-contiguously at the corners, at half-way along the edges and at the centre of the five by five chunky pixels block. A total of nine dark chunky pixels out of twenty-five.

Green would be represented by a broad top left to bottom right diagonal and one chunk in the bottom left corner and one chunk in the top right corner. A total of fifteen dark chunky pixels out of twenty-five: in fact, three in each row and three in each column.

Purple would be represented by a broad top right to bottom left diagonal and one chunk in the bottom right corner and one chunk in the top left corner. A total of fifteen dark chunky pixels out of twenty-five: in fact, three in each row and three in each column.

There is scope for additional colours to be represented by adding new ideas.

Brown could be represented by copying the left two columns of red as the left two columns of brown together with copying the right three columns of green as the right three columns of brown. A total of fourteen dark chunky pixels out of twenty-five.

Black presents an interesting problem. It could be twenty-five dark chunks; or it could be twenty-one dark chunks with four light chunks neither at the edge nor the centre; or it could be sixteen dark chunks around the edge and nine light chunks in the middle. The design with sixteen dark chunks around the edge and nine light chunks in the middle might be best as it might perhaps be more easily recognized.

Pink could be expressed using a copy of red with the three centre chunks of the middle vertical line deleted. A total of twelve dark chunky pixels out of twenty-five.

Light blue could be expressed using a copy of blue with the three centre chunks of the middle horizontal line deleted. A total of twelve dark chunky pixels out of twenty-five.

A greyed-out XO could be represented by a block which has the left edge column and the right edge column and the bottom edge row all dark. A total of thirteen dark chunky pixels out of twenty-five.