This oscillating fan is made with only 34 parts. It is just a demo, to show us how the oscillator works. If you replace part 99012 with 89509 (from lego set-9688), It will works better ...
The original idea is from SSunday ( http://www.lelezhen.com/forum.php?mod=viewthread&tid=36315 ).
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These types of files are created with the LDraw system of software. You will need to install compatible software to open and view the instructions. A full list of available software is on the LDraw site.