Mjb67 writes: Here's another good one, which seems to me to be related (wikizens please decide for yourselves, and correct if possible my mistakes). I have, at work, a function that includes a Dirac distribution. I have to integrate said function. The only way I have of evaluating said function is by point sampling it. A Dirac distribution or function is a function that is 0 when point sampled, yet integrates (over -infinity to infinity) to 1. Lovely! The practical application, by the way, is the total light coming from a perfect mirror towards the eye, found by integrating the light coming in from all directions multiplied by the scattering formula for a mirror (which is 0 for all incoming directions apart from the reflected direction).