substrate man page

substrate — Grow crystal-like lines on a computational substrate


substrate [-display host:display.screen] [-foreground color] [-background color] [-wireframe] [-max-cycles cyclecount] [-growth-delay delayms] [-initial-cracks numinitial] [-max-cracks nummax] [-sand-grains numgrains] [-circle-percent circlepercent] [-fps]


Lines like crystals grow on a computational substrate.  A simple  perpendicular growth rule creates intricate city-like structures.  Optionally, cracks may also be circular, producing a cityscape more familiar to places for which city planning is a distant, theoretical concern.

Ported from the code by j.tarbell at


substrate accepts the following options:

-wireframe (Default: False)

Don't draw sand-painting colored effects, only make a wireframe.

-max-cycles cyclecount (Default: 10000)

Maximum number of growth cycles before restarting.  The higher this is, the more complex the art.

-growth-delay delayms (Default: 18000)

Delay in ms between growth cycles.  More delay, slower (but smoother and less CPU intensive) art.

-initial-cracks numinitial (Default: 3)

Initial number of cracks in the substrate

-max-cracks nummax (Default: 100)

Maximum number of cracks in the substrate at a single time

-sand-grains numgrains (Default: 64)

Number of sand grains dropped during coloring.  More grains cause  a denser colour but use more cpu power.

-circle-percent circlepercent (Default: 0)

The percentage of the cracks will be circular.


Display the current frame rate and CPU load.



to get the default host and display number.


to get the name of a resource file that overrides the global resources stored in the RESOURCE_MANAGER property.

See Also

X(1), xscreensaver(1)


J. Tarbell <>, Jun-03

Mike Kershaw <>, Oct-04


5.37-6.fc27.1 (15-Aug-2017) X Version 11 XScreenSaver manual