A black and white pixel appears, corrupting the energy bar.

It represents itself as randomly occurring white and black pixels.

Thus if we have a black pixel on a white background it will vanish.

Each black pixel in the original logo is split into two complementary small blocks.

While a black pixel in the secret image is encoded using a matrix from the following set:

And it would see a whole scan line across the fax of black pixels.

So a scan line beginning with $03 would have the first two pixel positions set as white (with the next 5 pixels black).

The signal shifts up or down a given amount to designate white or black pixels.

A deviation less than that for a white or black pixel is taken to be a shade of grey.

The maximum resolution was 64 x 44 pixels black and white, for graphic plotting.