Spinorial tools have recently come back to fashion in loop gravity and spin
foams. They provide an elegant tool relating the standard holonomy-flux algebra
to the twisted geometry picture of the classical phase space on a fixed graph,
and to twistors. In these lectures we provide a brief and technical
introduction to the formalism and some of its applications.Comment: 16 pages; to appear in the Proceedings of the 3rd Quantum Gravity and
Quantum Geometry School, February 28 - March 13, 2011 Zakopane, Poland. v2:
minor amendment