"We continue this protocol until the future date (1 May 2010) at which time we upload our final version of the master document. For this final version, we include the URL of a web site where the .pdf documents of all of our past forecasts can be downloaded and independently checked for consistent MD5 and SHA-2 hashes. For convenience, we will include a summary of all of our forecasts in this final document."

"Suppose you are given a simple closed curve in the plane. (“Simple” means the curve does not intersect itself, “closed” means the curve ends at the same point where it begins.) Can you always find four points on the curve which form the vertices of a square?"