PoseBook 3D by Silver is a free Android app that is designed to be a self-controlled tool for artists to practice their construction and rotation of heads. It offers a great way to understand how forms move in space and helps users to draw the same head in multiple angles. This app is also a great tool for painters who wish to use it as a lighting reference for shadows. PoseBook 3D is created by Silver, who was inspired by the work of Andrew Loomis and George Bridgman, two great teachers who taught him the importance of rotating forms in space.