Space Police Ship (Z Ships arc).
Instructions for models used in Tranquility Base Comic. Originally published in 2011 as bonus comic content.
These instructions are free and (to borrow a concept) "open source": feel free to use them, modify them or whatever. Don't repackage or sell them though -- that would be a sucky move.
Or, more formally: These instructions are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
All instructions have been made using MLCad and LPub, both part of the LDraw system of tools available at www.ldraw.org.