Normal distribution sliced to show "68-95-99.7 Rule"

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One of the most important topics studied in probability and statistics is the Normal Distribution. The outcomes of many natural phenomena follow the pattern of the Normal Distribution. One property of a Normal Distribution is known as the "68-95-99.7 Rule". This rule states that roughly 68% of the outcomes would occur within one standard deviation (higher or lower) of the center (also called the mean) of the distribution. About 95% occur within two standard deviations or the mean, and 99.7% are within three standard deviations. The Thing provided here allows students to explore the 68-95-99.7 Rule by cutting the Normal Distribution into pieces which are one standard-deviation wide. Each piece is labeled with the approximate percentage of the outcomes which that piece represents. The pieces can be combined in various ways and the proportion of the total outcomes can be obtained by adding the percentages together. The middle two pieces add up to 68%. The middle four add up to 95%. If you add all six pieces together, it totals 99.7%. Note: The pieces do NOT cover the remaining 0.3% (the highest or lowest 0.15%) because the Normal Distribution extends outward indefinitely, and is too long and thin to 3-D print effectively. The pieces, as printed, are rotated and packed together to make a reasonably large version of the entire model printable at one time. Instructions This Thing was designed using MasterCAM software, which is usually used to program numerically controlled mills and lathes. The original shape of the normal distribution curve was created using the equation y = exp(-0.5x^2) / sqrt(2 pi)