Ceccecs were two-dimensional pseudo-forms, with low resolution and monochrome to save bandwidth. They were generated by block transfer computation. They crackled and flickered, a result of compression artefacts resulting from the algorithm used to generate them. They could electrocute people by floating into them. (PROSE: The Tomorrow Windows)
Behind the scenes[]
A Ceccec appears to the Eighth Doctor (PROSE: The Tomorrow Windows DWM 344 preview)
A Ceccec was depicted in the DWM 344 comic preview of The Tomorrow Windows, which is not considered a valid source for images on this wiki.