Reams of paper come in a standardised system of related sheet sizes. Most people are familiar with the international paper sizes A4, A3 and B4, but there are others. The ratio of the sides of any sheet in the series is such that if the paper is cut or folded in half on itself then the ratio of the sides remains unchanged. Due to this property of constant proportions when folding, artwork will enlarge or reduce photographically to fit any international paper size. In this article, the author performs some mathematical magic with an A4 sheet in a topological sense and shows how to cut a hole in this sheet so that an average-sized adult can easily pass through the hole without ripping the paper. (Contains 3 figures and 2 tables.)