On the 4th of May 2015 we've started to transition the project to the Public Domain. See this forum post
All of the old assets were licensed CC-BY 3.0
Not all of the authors of existing work have been reached, and one who has been reached has not agreed to release the rights to their work. This page hosts the collection of all the CC-BY-3.0 images of the OPP. If you wish to use these images, you will have to credit the owners. These images will not be included in future OPP packages, and should not be used as a base image for new work.
Authors who's work remains licensed CC-BY-3.0
Numberplay created the original version of this house.