- Initial Release Date
- Unknown, likely 1987
- Color Palette
- Max Resolution
- License Status
- © International Business Machines
- x86 Assembly
- Dan Butterfield
Tunnel is probably one of the earliest pieces of eyecandy software. It's not only one of the earliest pieces of eyecandy, it's also one of the earlier hardware demos, showing off the 256 color palette of the VGA adapter.
It was an internal IBM test program for VGA adapters, not originally intended for outside distribution. It along with another program, known internally as "Dazzle", but distributed as "O-My-God", were bits of eyecandy that leaked out of IBM and spread quickly through BBSs of the time.
Though running with 256 colors, only 255 colors are used for palette rotation, as one entry assigned to the rightmost column and the left corners remains black. Such was likely done so there would be an odd number of columns so the circles rendered could reduce to a single pixel instead of four.