Really two questions: 1. In the Do-It-Yourself Quantum Eraser article written by Rachel Hillmer and Paul Kwiat (published in Scientific American, May 2007), on page 93 there are instructions to cut in half horizontally a D-orientated (45 degrees clockwise from V), and an A-orientated (45 degrees counterclockwise from V), polariser and join them together. Are there such polarisers that are orientated as the final product of doing the above, but are applicable to a single photon passing through it (so either the photon will be 45 degrees polarised, or 135 degrees polarised)? 2. If a V polarised photon is tested in the polariser described above, because it has 1/2 probability of passing or failing the 45 degree, and 135 degree, tests, if it fails the 45 degree polariser, is it a candidate of now having probability 1 of passing the 135 degree polariser, or still 1/2 probability of passing the 135 degree polariser?