Provided by:
xscreensaver-gl-extra_5.04-4ubuntu1_i386 
NAME
blocktube - draws a swirling, falling tunnel of reflective slabs
SYNOPSIS
blocktube [-display host:display.screen] [-visual visual] [-window]
[-root] [-delay number] [-holdtime number] [-changetime number] [-no-
texture] [-no-fog] [-wireframe] [-fps]
DESCRIPTION
Blocktube draws a swirling, falling tunnel of reflective slabs. They
fade from hue to hue.
OPTIONS
-visual visual
Specify which visual to use. Legal values are the name of a
visual class, or the id number (decimal or hex) of a specific
visual.
-window Draw on a newly-created window. This is the default.
-root Draw on the root window.
-delay number
Per-frame delay, in microseconds. Default: 40000 (0.04
seconds.).
-holdtime number
How long to stay on the same color. Default: 1000 frames.
-changetime number
How long it takes to fade to a new color. Default: 200 frames.
-no-texture
Draw solid blocks intstead of reflective blocks.
-no-fog Do not make blocks in the distance be darker.
-wireframe
Only draw outlines.
-fps | -no-fps
Whether to show a frames-per-second display at the bottom of
the screen.
ENVIRONMENT
DISPLAY to get the default host and display number.
XENVIRONMENT
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)
COPYRIGHT
Copyright © 2003 by Lars Damerow. Permission to use, copy, modify,
distribute, and sell this software and its documentation for any
purpose is hereby granted without fee, provided that the above
copyright notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting documentation.
No representations are made about the suitability of this software for
any purpose. It is provided "as is" without express or implied
warranty.
AUTHOR
Lars Damerow <lars@oddment.org>